NilsML/retriever_dataset · Datasets at Hugging Face

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The biggest drawback of what type of reproduction is lack of genetic variation, since all offspring are identical?	sexual reproduction	meiosis	organic reproduction	asexual reproduction	In asexual reproduction, all the offspring are exactly the same. This is the biggest drawback of this type of reproduction. Why? Lack of genetic variation increases the risk of extinction. Without variety, there may be no organisms that can survive a major change in the environment.
What is the name given to the daily wake/sleep cycle?	variable rhythms	nocturnal rhythms	behavioral rhythms	circadian rhythms	Daily cycles of behavior, including sleeping a waking, are called circadian rhythms.
Where is the seafloor youngest?	sand bars	inland	deep currents	mid-ocean	Seafloor is youngest near the mid-ocean ridges and gets progressively older with distance from the ridge. Orange areas show the youngest seafloor. The oldest seafloor is near the edges of continents or deep sea trenches.
What is the term for the interaction of waves with other waves?	shockwave	current	tsunami	wave interference	Wave interference is the interaction of waves with other waves.
Filter feeders called rotifers collect digestive and excretory wastes in what primitive organ?	liver	bile duct	simple stomach	cloacal bladder	The rotifers are filter feeders that will eat dead material, algae, and other microscopic living organisms, and are therefore very important components of aquatic food webs. Rotifers obtain food that is directed toward the mouth by the current created from the movement of the corona. The food particles enter the mouth and travel to the mastax (pharynx with jawlike structures). Food then passes by digestive and salivary glands, and into the stomach, then onto the intestines. Digestive and excretory wastes are collected in a cloacal bladder before being released out the anus.
What mass of abnormal cells do cancer cells cause?	sebaceous cyst	bacteria	inflammation	tumor	Cancer cells grow rapidly and may form a mass of abnormal cells called a tumor.
Ultraviolet light has higher frequencies and shorter wavelengths than visible light, which means it has more what?	length	width	pressure	energy	Ultraviolet light has shorter wavelengths and higher frequencies than visible light. Ultraviolet light also has more energy, which makes it useful for killing germs. Too much exposure to ultraviolet light can damage the skin.
What planet has a surface temperature of over 400 degrees celsius, no oxygen, an atomsphere comprised mainly of carbon dioxide and tremendous atmospheric pressure?	Mars	uranus	Earth	venus	The atmosphere of Venus is markedly different from that of Earth. The gases in the Venusian atmosphere are 96.5% carbon dioxide and 3% nitrogen. The atmospheric pressure on Venus is roughly 92 times that of Earth, so the amount of nitrogen on Venus would contribute a pressure well over 2700 mm Hg. And there is no oxygen present, so we couldn’t breathe there. Not that we would want to go to Venus – the surface temperature is usually over 460°C.
Which is the body system that normally fights infections and defends against other causes of disease?	reproductive system	circulatory system	infectious system	immune system	The immune system is the body system that normally fights infections and defends against other causes of disease. When the immune system is working well, it usually keeps you from getting sick. But like any other body system, the immune system can have problems and develop diseases. Two types of immune system diseases are autoimmune diseases and allergies.
What is used to calculate ejection fraction?	umts	cns	rws	svs	SVs are also used to calculate ejection fraction, which is the portion of the blood that is pumped or ejected from the heart with each contraction. To calculate ejection fraction, SV is divided by EDV. Despite the name, the ejection fraction is normally expressed as a percentage. Ejection fractions range from approximately 55–70 percent, with a mean of 58 percent.
How does a sexually transmitted infection spread?	dramatic contact	enviromental contact	linear contact	sexual contact	A sexually transmitted infection (STI) is an infection that spreads through sexual contact. STIs are caused by pathogens , a living thing or virus that causes infection. The pathogens enter the body through the reproductive organs. Many STIs also spread through body fluids, such as blood. For example, a shared tattoo needle is one way an STI could spread. Some STIs can also spread from a mother to her baby during childbirth.
Stem cells are unspecialized cells that can reproduce themselves via cell division, sometimes after years of inactivity. under certain conditions, they may differentiate into tissue-specific or organ-specific cells with special these?	enzymes	chromosomes	mutations	functions	Stem Cells and Repair of Kidney Damage Stem cells are unspecialized cells that can reproduce themselves via cell division, sometimes after years of inactivity. Under certain conditions, they may differentiate into tissue-specific or organ-specific cells with special functions. In some cases, stem cells may continually divide to produce a mature cell and to replace themselves. Stem cell therapy has an enormous potential to improve the quality of life or save the lives of people suffering from debilitating or lifethreatening diseases. There have been several studies in animals, but since stem cell therapy is still in its infancy, there have been limited experiments in humans. Acute kidney injury can be caused by a number of factors, including transplants and other surgeries. It affects 7–10 percent of all hospitalized patients, resulting in the deaths of 35–40 percent of inpatients. In limited studies using mesenchymal stem cells, there have been fewer instances of kidney damage after surgery, the length of hospital stays has been reduced, and there have been fewer readmissions after release. How do these stem cells work to protect or repair the kidney? Scientists are unsure at this point, but some evidence has shown that these stem cells release several growth factors in endocrine and paracrine ways. As further studies are conducted to assess the safety and effectiveness of stem cell therapy, we will move closer to a day when kidney injury is rare, and curative treatments are routine.
What is the process of soil dissolving in rain called?	migration	abrasion	sedimentation	erosion	Mechanical weathering increases the rate of chemical weathering. As rock breaks into smaller pieces, the surface area of the pieces increases. With more surfaces exposed, there are more places for chemical weathering to occur. Let’s say you wanted to make some hot chocolate on a cold day. It would be hard to get a big chunk of chocolate to dissolve in your milk or hot water. Maybe you could make hot chocolate from some smaller pieces like chocolate chips, but it is much easier to add a powder to your milk. This is because the smaller the pieces are, the more surface area they have. Smaller pieces dissolve more easily.
What are all living things on earth formed of?	iron compounds	dioxide compounds	hydrogen compounds	carbon compounds	Introduction All living things on earth are formed mostly of carbon compounds. The prevalence of carbon compounds in living things has led to the epithet “carbon-based” life. The truth is we know of no other kind of life. Early chemists regarded substances isolated from organisms (plants and animals) as a different type of matter that could not be synthesized artificially, and these substances were thus known as organic compounds. The widespread belief called vitalism held that organic compounds were formed by a vital force present only in living organisms. The German chemist Friedrich Wohler was one of the early chemists to refute this aspect of vitalism, when, in 1828, he reported the synthesis of urea, a component of many body fluids, from nonliving materials. Since then, it has been recognized that organic molecules obey the same natural laws as inorganic substances, and the category of organic compounds has evolved to include both natural and synthetic compounds that contain carbon. Some carbon-containing compounds are not classified as organic, for example, carbonates and cyanides, and simple oxides, such as CO and CO2. Although a single, precise definition has yet to be identified by the chemistry community, most agree that a defining trait of organic molecules is the presence of carbon as the principal element, bonded to hydrogen and other carbon atoms. Today, organic compounds are key components of plastics, soaps, perfumes, sweeteners, fabrics, pharmaceuticals, and many other substances that we use every day. The value to us of organic compounds ensures that organic chemistry is an important discipline within the general field of chemistry. In this chapter, we discuss why the element carbon gives rise to a vast number and variety of compounds, how those compounds are classified, and the role of organic compounds in representative biological and industrial settings.
What is another name for critical speed?	impossible velocity	normal speed	gravity	terminal speed	accelerate indefinitely (as it would if we neglect air resistance, for example). Instead, viscous drag increases, slowing acceleration, until a critical speed, called the terminal speed, is reached and the acceleration of the object becomes zero. Once this happens, the object continues to fall at constant speed (the terminal speed). This is the case for particles of sand falling in the ocean, cells falling in a centrifuge, and sky divers falling through the air. Figure 12.19 shows some of the factors that affect terminal speed. There is a viscous drag on the object that depends on the viscosity of the fluid and the size of the object. But there is also a buoyant force that depends on the density of the object relative to the fluid. Terminal speed will be greatest for low-viscosity fluids and objects with high densities and small sizes. Thus a skydiver falls more slowly with outspread limbs than when they are in a pike position—head first with hands at their side and legs together. Take-Home Experiment: Don’t Lose Your Marbles By measuring the terminal speed of a slowly moving sphere in a viscous fluid, one can find the viscosity of that fluid (at that temperature). It can be difficult to find small ball bearings around the house, but a small marble will do. Gather two or three fluids (syrup, motor oil, honey, olive oil, etc. ) and a thick, tall clear glass or vase. Drop the marble into the center of the fluid and time its fall (after letting it drop a little to reach its terminal speed). Compare your values for the terminal speed and see if they are inversely proportional to the viscosities as listed in Table 12.1. Does it make a difference if the marble is dropped near the side of the glass? Knowledge of terminal speed is useful for estimating sedimentation rates of small particles. We know from watching mud settle out of dirty water that sedimentation is usually a slow process. Centrifuges are used to speed sedimentation by creating accelerated frames in which gravitational acceleration is replaced by centripetal acceleration, which can be much greater, increasing the terminal speed.
Prokaryotes are much simpler than what in many of their features?	microorganisms	meteorites	membranes	eukaryotes	14.2 DNA Structure and Sequencing The currently accepted model of the double-helix structure of DNA was proposed by Watson and Crick. Some of the salient features are that the two strands that make up the double helix are complementary and anti-parallel in nature. Deoxyribose sugars and phosphates form the backbone of the structure, and the nitrogenous bases are stacked inside. The diameter of the double helix, 2 nm, is uniform throughout. A purine always pairs with a pyrimidine; A pairs with T, and G pairs with C. One turn of the helix has ten base pairs. During cell division, each daughter cell receives a copy of the DNA by a process known as DNA replication. Prokaryotes are much simpler than eukaryotes in many of their features. Most prokaryotes contain a single, circular chromosome. In general, eukaryotic chromosomes contain a linear DNA molecule packaged into nucleosomes, and have two distinct regions that can be distinguished by staining, reflecting different states of packaging and compaction.
Which two atoms are found in most organic compounds?	magnesium and carbon	hydrogen and magnesium	potassium and carbon	hydrogen and carbon	null
How are heat changes in chemical reactions measured?	watts	velocities	amperes	joules	Heat changes in chemical reactions are typically measured in joules rather than calories. The conversion between a joule and a calorie is shown below.
What is a genetic disorder in which blood fails to clot properly because a normal clotting factor in the blood is lacking?	anemia	hypertension	sickle cell	hemophilia	Hemophilia is a genetic disorder in which blood fails to clot properly because a normal clotting factor in the blood is lacking. In people with hemophilia, even a minor injury can cause a life-threatening loss of blood. Most cases of hemophilia are caused by a recessive gene on the X chromosome. The disorder is expressed much more commonly in males because they have just one X chromosome.
Fungi that reproduce sexually create what?	a chromoplast	an ova	a sperm cell	a zygospore	Fungi can reproduce sexually to create a zygospore.
A long strip of sand is referred to as what?	a composition island	a volcano	a component island	a barrier island	A barrier island is a long strip of sand. The sand naturally moves in the local currents. People try to build on barrier islands.
Which viruses are being studied for cancer treatments?	osteophobic viruses	endophytic viruses	astringent viruses	oncolytic viruses	Viruses that infect cancer cells are being studied for their use in cancer treatments. Oncolytic viruses are viruses that lyse and kill cancer cells. Some researchers are hoping to treat some cancers with these viruses.
Mercury looks a lot like earth's moon. why do you think it does? both have been struck by a lot of what?	particles	floods	waves	asteroids	Mercury looks a lot like Earth's Moon. Why do you think it does? Both have been struck by a lot of asteroids. Both have no atmosphere, so there is no weathering and erosion. If they had an atmosphere, many of the craters would have been eroded away. Both have no plate tectonics to transform the landscape. This would also remove a lot of craters.
What is the smallest particle of an element that still has the properties of that element?	neutron	electron	nucleus	atom	The smallest particle of an element that still has the properties of that element is the atom. All the atoms of an element are like one another, and are different from the atoms of all other elements.
What is the three-dimensional structure of a single polypeptide called?	immature structure	immature Structure	Cysteine structure	tertiary structure	Tertiary structure refers to the three-dimensional structure of a single polypeptide. The alpha-helices and beta-sheets are folded into a compact globule structure. Stability is maintained through hydrogen bonds, disulfide bonds and other interactions.
What term is used to descibe the movement of molecules from an area of high concentration of the molecules to an area with a lower concentration?	permeation	radiation	convection	diffusion	Diffusion is the movement of molecules from an area of high concentration of the molecules to an area with a lower concentration. For cell transport, diffusion is the movement of small molecules across the cell membrane. The difference in the concentrations of the molecules in the two areas is called the concentration gradient . The kinetic energy of the molecules results in random motion, causing diffusion. In simple diffusion, this process proceeds without the aid of a transport protein. it is the random motion of the molecules that causes them to move from an area of high concentration to an area with a lower concentration.
A source of what is needed to disturb matter and start a mechanical wave?	respiration	magnetism	hydrogen	energy	The waves in the picture above are examples of mechanical waves. A mechanical wave is a disturbance in matter that transfers energy through the matter. A mechanical wave starts when matter is disturbed. A source of energy is needed to disturb matter and start a mechanical wave.
Much of the damage from hurricanes may be caused by?	hail	insurance fraud	wind chill	storm surge	A hurricane is a large storm with high winds and heavy rains. Hurricanes develop from tropical cyclones. They form over warm ocean water. Much of the damage from hurricanes may be caused by storm surge.
Color blindness, hemophilia and muscular dystrophy are three x-linked what?	alleles	genes	chromosomes	phenotypes	Color blindness, hemophilia and muscular dystrophy are three x-linked phenotypes.
An apocrine sweat gland is usually associated with hair follicles in densely hairy areas, such as armpits and genital regions. apocrine sweat glands are larger than eccrine sweat glands and lie deeper in the dermis, sometimes even reaching this?	stratum corneum	epidermis	papillary dermis	hypodermis	An apocrine sweat gland is usually associated with hair follicles in densely hairy areas, such as armpits and genital regions. Apocrine sweat glands are larger than eccrine sweat glands and lie deeper in the dermis, sometimes even reaching the hypodermis, with the duct normally emptying into the hair follicle. In addition to water and salts, apocrine sweat includes organic compounds that make the sweat thicker and subject to bacterial decomposition and subsequent smell. The release of this sweat is under both nervous and hormonal control, and plays a role in the poorly understood human pheromone response. Most commercial antiperspirants use an aluminum-based compound as their primary active ingredient to stop sweat. When the antiperspirant enters the sweat gland duct, the aluminum-based compounds precipitate due to a change in pH and form a physical block in the duct, which prevents sweat from coming out of the pore.
What is the only way to transfer thermal energy without matter?	evaporation	ultraviolet light	osmosis	radiation	Thermal radiation is one of three ways that thermal energy can be transferred. The other two ways are conduction and convection, both of which need matter to transfer energy. Radiation is the only way of transferring thermal energy that doesn’t require matter. To learn more about thermal radiation, watch “Radiation” at the URL below.
When plants are shut off from environmental cues they become?	extinct	synchronized	pollinated	desynchronized	null
What part of vertebrates integrates the endocrine and nervous systems?	the notochord	the cerebellum	the forebrain	the hypothalamus	null
An individual grows quickly and develops new abilities during infancy and?	adulthood	embryonic stage	senior years	childhood	An individual grows quickly and develops new abilities during infancy and childhood.
Prokaryotes are unicellular organisms that lack organelles surrounded by what?	tissues	particles	cells	membranes	The Prokaryotic Cell Recall that prokaryotes (Figure 13.5) are unicellular organisms that lack organelles surrounded by membranes. Therefore, they do not have a nucleus but instead have a single chromosome—a piece of circular DNA located in an area of the cell called the nucleoid. Most prokaryotes have a cell wall lying outside the plasma membrane. The composition of the cell wall differs significantly between the domains Bacteria and Archaea (and their cell walls also differ from the eukaryotic cell walls found in plants and fungi. ) The cell wall functions as a protective layer and is responsible for the organism’s shape. Some other structures are present in some prokaryotic species, but not in others. For example, the capsule found in some species enables the organism to attach to surfaces and protects it from dehydration. Some species may also have flagella (singular, flagellum) used for locomotion, and pili (singular, pilus) used for attachment to surfaces and to other bacteria for conjugation. Plasmids, which consist of small, circular pieces of DNA outside of the main chromosome, are also present in many species of bacteria.
What part of a plant is the food making factory?	the main stem	the growing tips	the roots	the leaves	null
What type of molecules do hydrogen bonds hold together?	carbon	gas	air	water	Hydrogen bonds hold adjacent water molecules together.
The greenhouse effect is associated with what negative phenomenon, blamed mainly on human activity?	advanced warming	cool warming	resulting warming	global warming	Recent global warming is due mainly to human actions. Burning fossil fuels adds carbon dioxide to the atmosphere. Carbon dioxide is a greenhouse gas. It’s one of several that human activities add to the atmosphere. An increase in greenhouse gases leads to greater greenhouse effect. The result is increased global warming. Figure below shows the increase in carbon dioxide since 1960.
What "color" (that is actually not a color at all) is associated with the absence of light?	clear	opaque	grey	black	The color of light that strikes an object may also affect the color that the object appears. For example, if only blue light strikes a red apple, the blue light is absorbed and no light is reflected. When no light reflects from an object, it looks black. Black isn’t a color. It is the absence of light.
What science is the study of matter and how it behaves?	geology	biology	geneology	chemistry	Chemistry is the study of matter and how it behaves.
What do we call the study of life and living things?	physics	chemistry	engineering	life science	Life science is the study of life and living things. Living things are also called organisms . Life science is often referred to as biology. Life scientists work in many different settings, from classrooms to labs to natural habitats. Dr. Katherine Smith, who is pictured in Figure below is a life scientist who works for NOAA (National Oceanic and Atmospheric Administration). She studies freshwater shrimp and fish in their natural habitats.
The average global temperature has been rising since the end of what era?	miocene	glacial	flintstone	pleistocene	The average global temperature has been rising since the end of the Pleistocene. With some ups and downs, of course. Rising temperatures are natural for this time period. But natural causes cannot explain all the warming that's been happening. There is some other factor at work.
What are animals that eat a prey animal?	scavengers	carnivores	herbivores	predators	Predators are animals that eat a prey animal. Scavengers eat organisms that are already dead. Decomposers break down dead plants and animals into component parts, including nutrients.
What are the only decomposers that can break down tough plant substances, including lignin and cellulose?	bacteria	flatworms	insects	fungi	Bacteria are also major decomposers, but they can grow and feed only on the exposed surfaces of organic matter. In contrast, fungi can use their hyphae to penetrate deep into organic matter. Fungi are also the only decomposers that can break down tough plant substances, including lignin (in wood) and cellulose (in plant cell walls). They have special enzymes to do this work. The enzymes are released by the tips of the hyphae. Because of these abilities, fungi are the primary decomposers in forests (see Figure below ).
What type of carbon compound is methane?	alternating compounds	dynamic organic compounds	stable compounds	volatile organic compounds	Volatile organic compounds (VOCs) are carbon compounds, such as methane. VOCs are released by many human activities. Raising livestock, for example, produces a lot of methane.
In diffusion, substances tend to move from an area of high concentration to an area of what kind of concentration?	Increase	drop	rise	low	Diffusion Diffusion is a passive process of transport. A single substance tends to move from an area of high concentration to an area of low concentration until the concentration is equal across a space. You are familiar with diffusion of substances through the air. For example, think about someone opening a bottle of ammonia in a room filled with people. The ammonia gas is at its highest concentration in the bottle; its lowest concentration is at the edges of the room. The ammonia vapor will diffuse, or spread away, from the bottle, and gradually, more and more people will smell the ammonia as it spreads. Materials move within the cell’s cytosol by diffusion, and certain materials move through the plasma membrane by diffusion (Figure 5.8). Diffusion expends no energy. On the contrary, concentration gradients are a form of potential energy, dissipated as the gradient is eliminated.
In what kind of state are particles fixed in place relative to one another?	liquid state	hybrid state	useful state	solid state	In the solid state, particles are fixed in place relative to one another. In the liquid and gas states, individual particles are free to move.
What is defined as the amount of energy needed to increase the temperature of one gram of water by 1°c. one calorie equals 4.184 joules?	fat	weight	sulfur	calorie	A related unit is the calorie. This term arose prior to the establishment of the SI system and is now replaced by the joule in most situations. One calorie is defined as the amount of energy needed to increase the temperature of one gram of water by 1°C. One calorie equals 4.184 joules. Note that this calorie is not exactly the same as the calories listed on food products. One food Calorie (usually written with a capital C) is equal to 1000 “regular” calories. Thus, a 140-Calorie snack can be fully digested to produce 140,000 calories of energy. We will use the SI unit joules in our discussions of heat energy.
About a third of all bacteria in the gut are members of what species?	trematodes	actinomyces	spirochetes	bacteroides	A wide range of friendly bacteria live in the gut. Bacteria begin to populate the human digestive system right after birth. Gut bacteria include Lactobacillus , the bacteria commonly used in probiotic foods such as yogurt, and E. coli bacteria. About a third of all bacteria in the gut are members of the Bacteroides species. Bacteroides are key in helping us digest plant food.
What form of feedback occurs when an accumulation of an end product slows the process that makes that product?	particular feedback	positive feedback	optimal feedback	negative feedback	null
What is the term for a disease in which the immune system makes an inflammatory response to a harmless antigen?	influenza	nausea	diabetes	allergy	An allergy is a disease in which the immune system makes an inflammatory response to a harmless antigen. Any antigen that causes an allergy is called an allergen. Allergens may be inhaled or ingested, or they may come into contact with the skin. Two common causes of allergies are shown in Figure below . Inhaling ragweed pollen may cause coughing and sneezing. Skin contact with oils in poison ivy may cause an itchy rash.
Why is it easier to move boxes on a wheeled dolly than by sliding them?	more total work	starting friction	increase surface tension	rolling friction	Rolling friction is friction that acts on objects when they are rolling over a surface. Rolling friction is much weaker than sliding friction or static friction. This explains why it is much easier to move boxes on a wheeled dolly than by carrying or sliding them. It also explains why most forms of ground transportation use wheels, including cars, 4-wheelers, bicycles, roller skates, and skateboards. Ball bearings are another use of rolling friction (see Figure below ). They allow parts of a wheel or other machine to roll rather than slide over one another.
What is the protein in red blood cells that transports oxygen in the bloodstream?	plasma	rH factor	insulin	hemoglobin	Hemoglobin is a protein in red blood cells that transports oxygen in the bloodstream. Scientists studied hemoglobin simply to learn how it worked. Out of this research came an understanding of how the protein changes shape when oxygen attaches to it. This information was then applied to help patients with sickle cell anemia, a disorder caused by an abnormal hemoglobin structure that makes hemoglobin molecules clump up when oxygen leaves the protein. Basic knowledge of protein structure led to an improved understanding of a wide-spread disease and opened the door for development of treatments.
Space shuttles are reusable vehicles designed to get astronauts where?	distant solar systems	underwater	the 6th dimension	space	Space shuttles are reusable vehicles for American astronauts to get into space.
Specialized peroxisomes called glyoxysomes are found in the fat-storing tissues of what?	chloroplasts	plant stems	plant leaves	plant seeds	null
The nervous system, together with what system, controls all the other organ systems?	limb system	skeletal system	reproductive system	endocrine system	The nervous system, together with the endocrine system, controls all the other organ systems. The nervous system sends one type of signal around the body, and the endocrine system sends another type of signal around the body. The endocrine system makes and releases chemical messenger molecules, or hormones, which tell other body parts that a change or a reaction is necessary. So what type of signal does the nervous system send?.
What is the physical breakdown of chunks of food into smaller pieces?	mechanical catalyst	mechanical accumulation	dissolving	mechanical digestion	Mechanical digestion is the physical breakdown of chunks of food into smaller pieces. This type of digestion takes place mainly in the mouth and stomach.
Technically, which cells are the only autotrophic parts of the plant?	brown	yellow	red	green	null
This is the study of evolutionary history of groups of related organisms?	paleontology	synonymy	phrenology	phylogeny	Phylogeny is the evolutionary history of group of related organisms. It is represented by a phylogenetic tree that shows how species are related to each other through common ancestors. A clade is a group of organisms that includes an ancestor and all of its descendants. It is a phylogenetic classification, based on evolutionary relationships.
What does urine leave the body through?	the vagina	the skin	the intestine	the urethra	process in which urine leaves the body through a sphincter at the end of the urethra.
What phase is pure chlorine present as?	liquid	oil/gas	mist	gas	null
When electrons from two atoms are each attracted to the nucleus of the other atom, what type of bond is formed?	electrochemical bond	hydrogen bond	ionic bond	covalent bond	Covalent bonds form when the electron clouds of two atoms overlap with each other. In a simple H 2 molecule, the single electron in each atom becomes attracted to the nucleus of the other atom in the molecule as the atoms come closer together. Other covalent bonds form in the same way as unpaired electrons from two atoms “match up” to form the bond. In a fluorine atom, there is an unpaired electron in one of the 2p orbitals. When a F 2 molecule forms, the 2p orbitals from each of the two atoms overlap to produce the F−F covalent bond. The overlapping orbitals do not have to be of the same type to form a covalent bond. For example, in a molecule of HF, the 1s orbital of the hydrogen atom overlaps with the 2p orbital of the fluorine atom ( Figure below ):.
Wave cut platforms are level areas formed by what?	glaciers	shock erosion	surge erosion	wave erosion	Wave-cut platforms are level areas formed by wave erosion. Since these platforms are above sea level, it means that either sea level was higher relative or the rock was lower.
Electronegativities are used to determine the polarity of covalent bonds. the polarity of a covalent bond can be judged by determining the difference of the electronegativities of what involved in the covalent bond?	three atoms	seven atoms	six atoms	two atoms	Electronegativities are used to determine the polarity of covalent bonds. The polarity of a covalent bond can be judged by determining the difference of the electronegativities of the two atoms involved in the covalent bond, as summarized in the following table: Electronegativity Difference.
What are the cell walls of fungi made of?	casein	lectin	proteins	chitin	The cell walls of fungi are made of chitin. Chitin is a tough carbohydrate that also makes up the outer skeleton of insects. The cell walls of plants are made of cellulose.
All the water in the open ocean is referred to as what zone, which is further divided by depth?	oceanic	terrestrial	aquatic	pelagic	Other ocean zones are farther from shore in the open ocean. All the water in the open ocean is called the pelagic zone. It is further divided by depth:.
How many embryonic cell layers do flatworms have?	five	two	four	three	Flatworms have three embryonic cell layers. They have a mesoderm layer in addition to ectoderm and endoderm layers. The mesoderm layer allows flatworms to develop muscle tissues so they can move easily over solid surfaces.
When gasoline is burned, what pollutant is produced?	oxygen	methane	fluorocarbons	carbon dioxide	Using gasoline to power automobiles affects the environment. The exhaust fumes from burning gasoline cause air pollution. These pollutants include smog and ground-level ozone. Air pollution is a big problem for cities where large numbers of people drive every day. Burning gasoline also produces carbon dioxide. This is a greenhouse gas and is a cause of global warming. Similar pollutants come from other forms of oil.
What kingdom of organisms is characterized by having sensory organs, movement, and internal digestion?	plants	bacteria	fungi	animals	Animals not only have specialized cells. Most animals also have tissues and organs. In many animals, organs form organ systems, such as a nervous system. Higher levels of organization allow animals to perform many complex functions. What can animals do that most other living things cannot? Most animals share these characteristics: sensory organs , movement , and internal digestion . All of them are illustrated in Figure below .
What is the base numbering system of metric units?	sixes	twos	ones	tens	Metric units use a base numbering system of 10. Thus a centimeter is ten times larger than a millimeter. A decimeter is 10 times larger than a centimeter and a meter is 10 times larger than a decimeter. Thus a meter is 100 times larger than a centimeter and 1000 times larger than a millimeter. Going the other way, one can say that there are 100 cm contained in a meter.
What do fungi lack which makes it impossible for them to use photosynthesis?	roots	ammonia	sodium	chlorophyll	Fungi lack chlorophyll, so they cannot make food by photosynthesis as plants can. Instead, they are heterotrophs, like animals. But they don’t have a mouth or teeth. So how do fungi “eat”? They get their nutrition by absorbing organic compounds from other organisms. The other organisms may be dead or alive, depending on the fungus.
Spicules are most conspicuously present in which class?	trichina	phylum	spirogyra	hexactinellida	Take an up-close tour (http://openstaxcollege. org/l/sponge_ride) through the sponge and its cells. The presence and composition of spicules/spongin are the differentiating characteristics of the three classes of sponges (Figure 28.4): Class Calcarea contains calcium carbonate spicules and no spongin, class Hexactinellida contains six-rayed siliceous spicules and no spongin, and class Demospongia contains spongin and may or may not have spicules; if present, those spicules are siliceous. Spicules are most conspicuously present in class Hexactinellida, the order consisting of glass sponges. Some of the spicules may attain giant proportions (in relation to the typical size range of glass sponges of 3 to 10 mm) as seen in Monorhaphis chuni, which grows up to 3 m long.
Most of the food that they bring to their chicks is very rich in what?	glucose	grains	proteins	lipids	null
Two plates may slide past each other in opposite directions, this is called what?	shearing plate boundary	downstream plate boundary	earthquake	transform plate boundary	Two plates may slide past each other in opposite directions. This is called a transform plate boundary. These plate boundaries experience massive earthquakes. The world’s best known transform fault is the San Andreas Fault in California ( Figure below ). At this fault, the Pacific and North American plates grind past each other. Transform plate boundaries are most common as offsets along mid-ocean ridges.
What term is used to describe elements with unstable nuclei?	waste	explosive	larvae	radioactive	Gamma rays are produced when radioactive elements decay. Radioactive elements are elements with unstable nuclei. To become more stable, the nuclei undergo radioactive decay. In this process, the nuclei give off energy and may also emit charged particles of matter. Types of radioactive decay include alpha, beta, and gamma decay. In alpha and beta decay, both particles and energy are emitted. In gamma decay , only energy, in the form of gamma rays, is emitted.
What is the third gene of lac operon in addition to lacz and lacy?	leya	Lacy	ghara	laca	The three genes of the lac operon are lacZ, lacY, and lacA. They encode proteins needed to digest lactose. The genes are expressed only in the presence of lactose.
The majority of species in the phylum chordata are found in what subphylum, which includes animals ranging from lampreys to mammals?	organelles	lophotrochozoa	tardigrada	vertebrates	Chordates The majority of species in the phylum Chordata are found in the subphylum Vertebrata, which include many species with which we are familiar. The vertebrates contain more than 60,000 described species, divided into major groupings of the lampreys, fishes, amphibians, reptiles, birds, and mammals. Animals in the phylum Chordata share four key features that appear at some stage of their development: a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail (Figure 15.33). In certain groups, some of these traits are present only during embryonic development. The chordates are named for the notochord, which is a flexible, rod-shaped structure that is found in the embryonic stage of all chordates and in the adult stage of some chordate species. It is located between the digestive tube and the nerve cord, and provides skeletal support through the length of the body. In some chordates, the notochord acts as the primary axial support of the body throughout the animal’s lifetime. In vertebrates, the notochord is present during embryonic development, at which time it induces the development of the neural tube and serves as a support for the developing embryonic body. The notochord, however, is not found in the postnatal stage of vertebrates; at this point, it has been replaced by the vertebral column (the spine). The dorsal hollow nerve cord is derived from ectoderm that sinks below the surface of the skin and rolls into a hollow tube during development. In chordates, it is located dorsally to the notochord. In contrast, other animal phyla possess solid nerve cords that are located either ventrally or laterally. The nerve cord found in most chordate embryos develops into the brain and spinal cord, which compose the central nervous system. Pharyngeal slits are openings in the pharynx, the region just posterior to the mouth, that extend to the outside environment. In organisms that live in aquatic environments, pharyngeal slits allow for the exit of water that enters the mouth during feeding. Some invertebrate chordates use the pharyngeal slits to filter food from the water that enters the mouth. In fishes, the pharyngeal slits are modified into gill supports, and in jawed fishes, jaw supports. In tetrapods, the slits are further modified into components of the ear and tonsils, since there is no longer any need for gill supports in these air-breathing.
Why is having grasping hands and feet important for primates?	foraging for food	migrating	protecting habitat	hang on trees	null
The rising and sinking of warm and cooler material is called what?	depression	diffusion	insulation	convection	Hot lower mantle material rises upwards ( Figure below ). As it rises, it cools. At the top of the mantle it moves horizontally. Over time it becomes cool and dense enough that it sinks. Back at the bottom of the mantle, it travels horizontally. Eventually the material gets to the location where warm mantle material is rising. The rising and sinking of warm and cooler material is convection. The motion described creates a convection cell.
What is the remarkable ring of light around the sun called?	laguna	panorama	magnetic halo	corona	A solar eclipse is kind of like a field trip to the Sun from Earth. You can see something (with special tinted glasses) that you don't usually see. The Sun has a remarkable ring of light around it. This is the corona. If you have a chance to see a solar eclipse, you should do it.
Particles in what state of matter do not experience any force of mutual attraction or repulsion?	liquid	plasma	solid	gas	Gas particles do not experience any force of attraction or repulsion with each other.
What is a type of plant tissue consisting of undifferentiated cells that can continue to divide and differentiate?	tuber	malignant	ganglion	meristem	The key to continued growth and repair of plant cells is meristem . Meristem is a type of plant tissue consisting of undifferentiated cells that can continue to divide and differentiate.
What are basic tools of the cell for organizing metabolism, transport, and storage of molecules?	vacuoles	tissues	membranes	vesicles	A vesicle is a small, spherical compartment that is separated from the cytosol by at least one lipid bilayer. Many vesicles are made in the Golgi apparatus and the endoplasmic reticulum, or are made from parts of the cell membrane. Vesicles from the Golgi apparatus can be seen in Figure above . Because it is separated from the cytosol, the space inside the vesicle can be made to be chemically different from the cytosol. Vesicles are basic tools of the cell for organizing metabolism, transport, and storage of molecules. Vesicles are also used as chemical reaction chambers. They can be classified by their contents and function.
The ileum is the last part of what organ, and is where the bile salts and vitamins are absorbed into blood stream?	stomach	large intestine	gall bladder	small intestine	The ileum, also illustrated in Figure 34.11 is the last part of the small intestine and here the bile salts and vitamins are absorbed into blood stream. The undigested food is sent to the colon from the ileum via peristaltic movements of the muscle. The ileum ends and the large intestine begins at the ileocecal valve. The vermiform, “worm-like,” appendix is located at the ileocecal valve. The appendix of humans secretes no enzymes and has an insignificant role in immunity. Large Intestine The large intestine, illustrated in Figure 34.13, reabsorbs the water from the undigested food material and processes the waste material. The human large intestine is much smaller in length compared to the small intestine but larger in diameter. It has three parts: the cecum, the colon, and the rectum. The cecum joins the ileum to the colon and is the receiving pouch for the waste matter. The colon is home to many bacteria or “intestinal flora” that aid in the digestive processes. The colon can be divided into four regions, the ascending colon, the transverse colon, the descending colon and the sigmoid colon. The main functions of the colon are to extract the water and mineral salts from undigested food, and to store waste material. Carnivorous mammals have a shorter large intestine compared to herbivorous mammals due to their diet.
Total internal reflections the princicple behind what type of optics?	Blindness	pipes optics	refined optics	fiber optics	Total internal reflection is the principle behind fiber optics . A bundle of fibers made out of glass or plastic only a few micrometers in diameter is called a light pipe since light can be transmitted along it with almost no loss. Light passing down the fibers makes glancing collisions with the walls so that total internal reflection occurs.
Which cells at the base of the hair root form the outer root sheath?	scala media	scala vestibuli	tunnel fibers	basal	Figure 5.12 Hair Follicle The slide shows a cross-section of a hair follicle. Basal cells of the hair matrix in the center differentiate into cells of the inner root sheath. Basal cells at the base of the hair root form the outer root sheath. LM × 4. (credit: modification of work by “kilbad”/Wikimedia Commons).
What is the term for sediment deposited by a glacier?	plateau	holocene	crater	moraine	Moraine is sediment deposited by a glacier. A ground moraine is a thick layer of sediments left behind by a retreating glacier. An end moraine is a low ridge of sediments deposited at the end of the glacier. It marks the greatest distance the glacier advanced.
Usually done on computers, what do you call sets of equations that take into account many factors to represent a phenomenon?	spreadsheets	fractals	analogous models	mathematical models	Mathematical models are sets of equations that take into account many factors to represent a phenomenon. Mathematical models are usually done on computers.
What is the mode of breathing that occurs at rest and does not require the cognitive thought of the individual?	forced breathing	conscious breathing	small breathing	quiet breathing	There are different types, or modes, of breathing that require a slightly different process to allow inspiration and expiration. Quiet breathing, also known as eupnea, is a mode of breathing that occurs at rest and does not require the cognitive thought of the individual. During quiet breathing, the diaphragm and external intercostals must contract. A deep breath, called diaphragmatic breathing, requires the diaphragm to contract. As the diaphragm relaxes, air passively leaves the lungs. A shallow breath, called costal breathing, requires contraction of the intercostal muscles. As the intercostal muscles relax, air passively leaves the lungs. In contrast, forced breathing, also known as hyperpnea, is a mode of breathing that can occur during exercise or actions that require the active manipulation of breathing, such as singing. During forced breathing, inspiration and expiration both occur due to muscle contractions. In addition to the contraction of the diaphragm and intercostal muscles, other accessory muscles must also contract. During forced inspiration, muscles of the neck, including the scalenes, contract and lift the thoracic wall, increasing lung volume. During forced expiration, accessory muscles of the abdomen, including the obliques, contract, forcing abdominal organs upward against the diaphragm. This helps to push the diaphragm further into the thorax, pushing more air out. In addition, accessory muscles (primarily the internal intercostals) help to compress the rib cage, which also reduces the volume of the thoracic cavity.
Rubber is what kind of solid?	porous	inorganic	aqueous	amorphous	When a tire goes flat, its shape changes. The tire might be flat because of a slow leak in the tire valve. It could be flat because it ran over a nail or screw and ended up with a small hole where the air can leak out over a period of time. Or it could go flat when it hits a large rock or other object while travelling at high speeds (this one is for those readers who enjoy detective movies or TV shows). What if a crystalline solid like LiBr were ever made into a tire (now there’s a weird idea)? When it encountered a blow, the crystal would break into small pieces. Since rubber is an amorphous solid, it has a very different set of physical properties.
What do birds do in mating season?	find many mates	migrate	reproduce asexually	pair up with the same bird	Yes. Birds do actually pair up each mating season, if not for life. And the male better be prepared to treat his female properly. There is actually an elaborate process in which the female chooses her mate.
What exciting and evolving field of physics finds that nature on the smallest scale may have its greatest influence on the large-scale character of the universe?	astrophysics	proteins physics	biophysics	particle physics	This chapter covers the basics of particle physics as we know it today. An amazing convergence of topics is evolving in particle physics. We find that some particles are intimately related to forces, and that nature on the smallest scale may have its greatest influence on the large-scale character of the universe. It is an adventure exceeding the best science fiction because it is not only fantastic, it is real.
In genetics, what does it mean when the amount is longer since the amount of time since a species diverged?	Less difference in DNA	greater making in dna	tilt differences in dna	greater differences in dna	Scientists can compare the DNA or proteins of different species. If the molecules are similar, this shows that the species are related. The more similar the molecules are, the closer the relationship is likely to be. When molecules are used in this way, they are called molecular clocks . This method assumes that random mutations occur at a constant rate for a given protein or segment of DNA. Over time, the mutations add up. The longer the amount of time since species diverged, the more differences there will be in their DNA or proteins.
Ragweed and poison ivy are common causes of what?	defects	cancers	mutations	allergies	Ragweed and poison ivy are common causes of allergies. Are you allergic to these plants?.
What type of distance is caused by the force you apply to a machine over a given distance?	response distance	accumulation distance	force distance	input distance	The force you apply to a machine is applied over a given distance, called the input distance. The force applied by the machine to the object is also applied over a distance, called the output distance. The output distance may or may not be the same as the input distance.
What is calculated by dividing the mass by the volume of a certain object?	median	radius	diameter	density	The density of a certain object is calculated by dividing the mass by the volume. Suppose that a mass of 37.46 g is divided by a volume of 12.7 cm 3 . The result on a calculator would be:.
Electric motors transform electrical energy into what other form of energy?	solar	magnetic	thermal	kinetic	An electric motor is a device that uses an electromagnet to change electrical energy to kinetic energy. Figure below shows a simple diagram of an electric motor. The motor contains an electromagnet that is connected to a shaft. When current flows through the motor, the electromagnet turns, causing the shaft to turn as well. The rotating shaft moves other parts of the device.
The bicoid maternal effect gene is transcribed in which cells of the mother?	cell walls	veteran cells	boy cells	nurse cells	The bicoid maternal effect gene is transcribed in the nurse cells of the mother and then the mRNA is transferred to the oocyte. Mutant embryos from homozygous mutant bicoid mothers fail to produce head and thorax structures.
How often an allele occurs in a gene pool relative to the other alleles for that gene is known as _______	genetic rate	allele succession	genomic frequency	allele frequency	Allele frequency is how often an allele occurs in a gene pool relative to the other alleles for that gene. Look at the example in Table below . The population in the table has 100 members. In a sexually reproducing species, each member of the population has two copies of each gene. Therefore, the total number of copies of each gene in the gene pool is 200. The gene in the example exists in the gene pool in two forms, alleles A and a . Knowing the genotypes of each population member, we can count the number of alleles of each type in the gene pool. The table shows how this is done.
If more coils are added to an electromagnet it becomes?	brighter	lighter	weaker	stronger	The combined magnetic force of the magnetized wire coil and iron bar makes an electromagnet very strong. In fact, electromagnets are the strongest magnets made. An electromagnet is stronger if there are more turns in the coil of wire or there is more current flowing through it. A bigger bar or one made of material that is easier to magnetize also increases an electromagnet’s strength. At the following URL, you can see an animation demonstrating how these factors affect the strength of an electromagnet. http://www. schoolphysics. co. uk/animations/Electromagnet/index. html.

The biggest drawback of what type of reproduction is lack of genetic variation, since all offspring are identical?

sexual reproduction

meiosis

organic reproduction

asexual reproduction

In asexual reproduction, all the offspring are exactly the same. This is the biggest drawback of this type of reproduction. Why? Lack of genetic variation increases the risk of extinction. Without variety, there may be no organisms that can survive a major change in the environment.

What is the name given to the daily wake/sleep cycle?

variable rhythms

nocturnal rhythms

behavioral rhythms

circadian rhythms

Daily cycles of behavior, including sleeping a waking, are called circadian rhythms.

Where is the seafloor youngest?

sand bars

inland

deep currents

mid-ocean

Seafloor is youngest near the mid-ocean ridges and gets progressively older with distance from the ridge. Orange areas show the youngest seafloor. The oldest seafloor is near the edges of continents or deep sea trenches.

What is the term for the interaction of waves with other waves?

shockwave

current

tsunami

wave interference

Wave interference is the interaction of waves with other waves.

Filter feeders called rotifers collect digestive and excretory wastes in what primitive organ?

liver

bile duct

simple stomach

cloacal bladder

The rotifers are filter feeders that will eat dead material, algae, and other microscopic living organisms, and are therefore very important components of aquatic food webs. Rotifers obtain food that is directed toward the mouth by the current created from the movement of the corona. The food particles enter the mouth and travel to the mastax (pharynx with jawlike structures). Food then passes by digestive and salivary glands, and into the stomach, then onto the intestines. Digestive and excretory wastes are collected in a cloacal bladder before being released out the anus.

What mass of abnormal cells do cancer cells cause?

sebaceous cyst

bacteria

inflammation

tumor

Cancer cells grow rapidly and may form a mass of abnormal cells called a tumor.

Ultraviolet light has higher frequencies and shorter wavelengths than visible light, which means it has more what?

length

width

pressure

energy

Ultraviolet light has shorter wavelengths and higher frequencies than visible light. Ultraviolet light also has more energy, which makes it useful for killing germs. Too much exposure to ultraviolet light can damage the skin.

What planet has a surface temperature of over 400 degrees celsius, no oxygen, an atomsphere comprised mainly of carbon dioxide and tremendous atmospheric pressure?

Mars

uranus

Earth

venus

The atmosphere of Venus is markedly different from that of Earth. The gases in the Venusian atmosphere are 96.5% carbon dioxide and 3% nitrogen. The atmospheric pressure on Venus is roughly 92 times that of Earth, so the amount of nitrogen on Venus would contribute a pressure well over 2700 mm Hg. And there is no oxygen present, so we couldn’t breathe there. Not that we would want to go to Venus – the surface temperature is usually over 460°C.

Which is the body system that normally fights infections and defends against other causes of disease?

reproductive system

circulatory system

infectious system

immune system

The immune system is the body system that normally fights infections and defends against other causes of disease. When the immune system is working well, it usually keeps you from getting sick. But like any other body system, the immune system can have problems and develop diseases. Two types of immune system diseases are autoimmune diseases and allergies.

What is used to calculate ejection fraction?

umts

cns

rws

svs

SVs are also used to calculate ejection fraction, which is the portion of the blood that is pumped or ejected from the heart with each contraction. To calculate ejection fraction, SV is divided by EDV. Despite the name, the ejection fraction is normally expressed as a percentage. Ejection fractions range from approximately 55–70 percent, with a mean of 58 percent.

How does a sexually transmitted infection spread?

dramatic contact

enviromental contact

linear contact

sexual contact

A sexually transmitted infection (STI) is an infection that spreads through sexual contact. STIs are caused by pathogens , a living thing or virus that causes infection. The pathogens enter the body through the reproductive organs. Many STIs also spread through body fluids, such as blood. For example, a shared tattoo needle is one way an STI could spread. Some STIs can also spread from a mother to her baby during childbirth.

Stem cells are unspecialized cells that can reproduce themselves via cell division, sometimes after years of inactivity. under certain conditions, they may differentiate into tissue-specific or organ-specific cells with special these?

enzymes

chromosomes

mutations

functions

Stem Cells and Repair of Kidney Damage Stem cells are unspecialized cells that can reproduce themselves via cell division, sometimes after years of inactivity. Under certain conditions, they may differentiate into tissue-specific or organ-specific cells with special functions. In some cases, stem cells may continually divide to produce a mature cell and to replace themselves. Stem cell therapy has an enormous potential to improve the quality of life or save the lives of people suffering from debilitating or lifethreatening diseases. There have been several studies in animals, but since stem cell therapy is still in its infancy, there have been limited experiments in humans. Acute kidney injury can be caused by a number of factors, including transplants and other surgeries. It affects 7–10 percent of all hospitalized patients, resulting in the deaths of 35–40 percent of inpatients. In limited studies using mesenchymal stem cells, there have been fewer instances of kidney damage after surgery, the length of hospital stays has been reduced, and there have been fewer readmissions after release. How do these stem cells work to protect or repair the kidney? Scientists are unsure at this point, but some evidence has shown that these stem cells release several growth factors in endocrine and paracrine ways. As further studies are conducted to assess the safety and effectiveness of stem cell therapy, we will move closer to a day when kidney injury is rare, and curative treatments are routine.

What is the process of soil dissolving in rain called?

migration

abrasion

sedimentation

erosion

Mechanical weathering increases the rate of chemical weathering. As rock breaks into smaller pieces, the surface area of the pieces increases. With more surfaces exposed, there are more places for chemical weathering to occur. Let’s say you wanted to make some hot chocolate on a cold day. It would be hard to get a big chunk of chocolate to dissolve in your milk or hot water. Maybe you could make hot chocolate from some smaller pieces like chocolate chips, but it is much easier to add a powder to your milk. This is because the smaller the pieces are, the more surface area they have. Smaller pieces dissolve more easily.

What are all living things on earth formed of?

iron compounds

dioxide compounds

hydrogen compounds

carbon compounds

Introduction All living things on earth are formed mostly of carbon compounds. The prevalence of carbon compounds in living things has led to the epithet “carbon-based” life. The truth is we know of no other kind of life. Early chemists regarded substances isolated from organisms (plants and animals) as a different type of matter that could not be synthesized artificially, and these substances were thus known as organic compounds. The widespread belief called vitalism held that organic compounds were formed by a vital force present only in living organisms. The German chemist Friedrich Wohler was one of the early chemists to refute this aspect of vitalism, when, in 1828, he reported the synthesis of urea, a component of many body fluids, from nonliving materials. Since then, it has been recognized that organic molecules obey the same natural laws as inorganic substances, and the category of organic compounds has evolved to include both natural and synthetic compounds that contain carbon. Some carbon-containing compounds are not classified as organic, for example, carbonates and cyanides, and simple oxides, such as CO and CO2. Although a single, precise definition has yet to be identified by the chemistry community, most agree that a defining trait of organic molecules is the presence of carbon as the principal element, bonded to hydrogen and other carbon atoms. Today, organic compounds are key components of plastics, soaps, perfumes, sweeteners, fabrics, pharmaceuticals, and many other substances that we use every day. The value to us of organic compounds ensures that organic chemistry is an important discipline within the general field of chemistry. In this chapter, we discuss why the element carbon gives rise to a vast number and variety of compounds, how those compounds are classified, and the role of organic compounds in representative biological and industrial settings.

What is another name for critical speed?

impossible velocity

normal speed

gravity

terminal speed

accelerate indefinitely (as it would if we neglect air resistance, for example). Instead, viscous drag increases, slowing acceleration, until a critical speed, called the terminal speed, is reached and the acceleration of the object becomes zero. Once this happens, the object continues to fall at constant speed (the terminal speed). This is the case for particles of sand falling in the ocean, cells falling in a centrifuge, and sky divers falling through the air. Figure 12.19 shows some of the factors that affect terminal speed. There is a viscous drag on the object that depends on the viscosity of the fluid and the size of the object. But there is also a buoyant force that depends on the density of the object relative to the fluid. Terminal speed will be greatest for low-viscosity fluids and objects with high densities and small sizes. Thus a skydiver falls more slowly with outspread limbs than when they are in a pike position—head first with hands at their side and legs together. Take-Home Experiment: Don’t Lose Your Marbles By measuring the terminal speed of a slowly moving sphere in a viscous fluid, one can find the viscosity of that fluid (at that temperature). It can be difficult to find small ball bearings around the house, but a small marble will do. Gather two or three fluids (syrup, motor oil, honey, olive oil, etc. ) and a thick, tall clear glass or vase. Drop the marble into the center of the fluid and time its fall (after letting it drop a little to reach its terminal speed). Compare your values for the terminal speed and see if they are inversely proportional to the viscosities as listed in Table 12.1. Does it make a difference if the marble is dropped near the side of the glass? Knowledge of terminal speed is useful for estimating sedimentation rates of small particles. We know from watching mud settle out of dirty water that sedimentation is usually a slow process. Centrifuges are used to speed sedimentation by creating accelerated frames in which gravitational acceleration is replaced by centripetal acceleration, which can be much greater, increasing the terminal speed.

Prokaryotes are much simpler than what in many of their features?

microorganisms

meteorites

membranes

eukaryotes

14.2 DNA Structure and Sequencing The currently accepted model of the double-helix structure of DNA was proposed by Watson and Crick. Some of the salient features are that the two strands that make up the double helix are complementary and anti-parallel in nature. Deoxyribose sugars and phosphates form the backbone of the structure, and the nitrogenous bases are stacked inside. The diameter of the double helix, 2 nm, is uniform throughout. A purine always pairs with a pyrimidine; A pairs with T, and G pairs with C. One turn of the helix has ten base pairs. During cell division, each daughter cell receives a copy of the DNA by a process known as DNA replication. Prokaryotes are much simpler than eukaryotes in many of their features. Most prokaryotes contain a single, circular chromosome. In general, eukaryotic chromosomes contain a linear DNA molecule packaged into nucleosomes, and have two distinct regions that can be distinguished by staining, reflecting different states of packaging and compaction.

Which two atoms are found in most organic compounds?

magnesium and carbon

hydrogen and magnesium

potassium and carbon

hydrogen and carbon

null

How are heat changes in chemical reactions measured?

watts

velocities

amperes

joules

Heat changes in chemical reactions are typically measured in joules rather than calories. The conversion between a joule and a calorie is shown below.

What is a genetic disorder in which blood fails to clot properly because a normal clotting factor in the blood is lacking?

anemia

hypertension

sickle cell

hemophilia

Hemophilia is a genetic disorder in which blood fails to clot properly because a normal clotting factor in the blood is lacking. In people with hemophilia, even a minor injury can cause a life-threatening loss of blood. Most cases of hemophilia are caused by a recessive gene on the X chromosome. The disorder is expressed much more commonly in males because they have just one X chromosome.

Fungi that reproduce sexually create what?

a chromoplast

an ova

a sperm cell

a zygospore

Fungi can reproduce sexually to create a zygospore.

A long strip of sand is referred to as what?

a composition island

a volcano

a component island

a barrier island

A barrier island is a long strip of sand. The sand naturally moves in the local currents. People try to build on barrier islands.

Which viruses are being studied for cancer treatments?

osteophobic viruses

endophytic viruses

astringent viruses

oncolytic viruses

Viruses that infect cancer cells are being studied for their use in cancer treatments. Oncolytic viruses are viruses that lyse and kill cancer cells. Some researchers are hoping to treat some cancers with these viruses.

Mercury looks a lot like earth's moon. why do you think it does? both have been struck by a lot of what?

particles

floods

waves

asteroids

Mercury looks a lot like Earth's Moon. Why do you think it does? Both have been struck by a lot of asteroids. Both have no atmosphere, so there is no weathering and erosion. If they had an atmosphere, many of the craters would have been eroded away. Both have no plate tectonics to transform the landscape. This would also remove a lot of craters.

What is the smallest particle of an element that still has the properties of that element?

neutron

electron

nucleus

atom

The smallest particle of an element that still has the properties of that element is the atom. All the atoms of an element are like one another, and are different from the atoms of all other elements.

What is the three-dimensional structure of a single polypeptide called?

immature structure

immature Structure

Cysteine structure

tertiary structure

Tertiary structure refers to the three-dimensional structure of a single polypeptide. The alpha-helices and beta-sheets are folded into a compact globule structure. Stability is maintained through hydrogen bonds, disulfide bonds and other interactions.

What term is used to descibe the movement of molecules from an area of high concentration of the molecules to an area with a lower concentration?

permeation

radiation

convection

diffusion

Diffusion is the movement of molecules from an area of high concentration of the molecules to an area with a lower concentration. For cell transport, diffusion is the movement of small molecules across the cell membrane. The difference in the concentrations of the molecules in the two areas is called the concentration gradient . The kinetic energy of the molecules results in random motion, causing diffusion. In simple diffusion, this process proceeds without the aid of a transport protein. it is the random motion of the molecules that causes them to move from an area of high concentration to an area with a lower concentration.

A source of what is needed to disturb matter and start a mechanical wave?

respiration

magnetism

hydrogen

energy

The waves in the picture above are examples of mechanical waves. A mechanical wave is a disturbance in matter that transfers energy through the matter. A mechanical wave starts when matter is disturbed. A source of energy is needed to disturb matter and start a mechanical wave.

Much of the damage from hurricanes may be caused by?

hail

insurance fraud

wind chill

storm surge

A hurricane is a large storm with high winds and heavy rains. Hurricanes develop from tropical cyclones. They form over warm ocean water. Much of the damage from hurricanes may be caused by storm surge.

Color blindness, hemophilia and muscular dystrophy are three x-linked what?

alleles

genes

chromosomes

phenotypes

Color blindness, hemophilia and muscular dystrophy are three x-linked phenotypes.

An apocrine sweat gland is usually associated with hair follicles in densely hairy areas, such as armpits and genital regions. apocrine sweat glands are larger than eccrine sweat glands and lie deeper in the dermis, sometimes even reaching this?

stratum corneum

epidermis

papillary dermis

hypodermis

An apocrine sweat gland is usually associated with hair follicles in densely hairy areas, such as armpits and genital regions. Apocrine sweat glands are larger than eccrine sweat glands and lie deeper in the dermis, sometimes even reaching the hypodermis, with the duct normally emptying into the hair follicle. In addition to water and salts, apocrine sweat includes organic compounds that make the sweat thicker and subject to bacterial decomposition and subsequent smell. The release of this sweat is under both nervous and hormonal control, and plays a role in the poorly understood human pheromone response. Most commercial antiperspirants use an aluminum-based compound as their primary active ingredient to stop sweat. When the antiperspirant enters the sweat gland duct, the aluminum-based compounds precipitate due to a change in pH and form a physical block in the duct, which prevents sweat from coming out of the pore.

What is the only way to transfer thermal energy without matter?

evaporation

ultraviolet light

osmosis

radiation

Thermal radiation is one of three ways that thermal energy can be transferred. The other two ways are conduction and convection, both of which need matter to transfer energy. Radiation is the only way of transferring thermal energy that doesn’t require matter. To learn more about thermal radiation, watch “Radiation” at the URL below.

When plants are shut off from environmental cues they become?

extinct

synchronized

pollinated

desynchronized

null

What part of vertebrates integrates the endocrine and nervous systems?

the notochord

the cerebellum

the forebrain

the hypothalamus

null

An individual grows quickly and develops new abilities during infancy and?

adulthood

embryonic stage

senior years

childhood

An individual grows quickly and develops new abilities during infancy and childhood.

Prokaryotes are unicellular organisms that lack organelles surrounded by what?

tissues

particles

cells

membranes

The Prokaryotic Cell Recall that prokaryotes (Figure 13.5) are unicellular organisms that lack organelles surrounded by membranes. Therefore, they do not have a nucleus but instead have a single chromosome—a piece of circular DNA located in an area of the cell called the nucleoid. Most prokaryotes have a cell wall lying outside the plasma membrane. The composition of the cell wall differs significantly between the domains Bacteria and Archaea (and their cell walls also differ from the eukaryotic cell walls found in plants and fungi. ) The cell wall functions as a protective layer and is responsible for the organism’s shape. Some other structures are present in some prokaryotic species, but not in others. For example, the capsule found in some species enables the organism to attach to surfaces and protects it from dehydration. Some species may also have flagella (singular, flagellum) used for locomotion, and pili (singular, pilus) used for attachment to surfaces and to other bacteria for conjugation. Plasmids, which consist of small, circular pieces of DNA outside of the main chromosome, are also present in many species of bacteria.

What part of a plant is the food making factory?

the main stem

the growing tips

the roots

the leaves

null

What type of molecules do hydrogen bonds hold together?

carbon

gas

air

water

Hydrogen bonds hold adjacent water molecules together.

The greenhouse effect is associated with what negative phenomenon, blamed mainly on human activity?

advanced warming

cool warming

resulting warming

global warming

Recent global warming is due mainly to human actions. Burning fossil fuels adds carbon dioxide to the atmosphere. Carbon dioxide is a greenhouse gas. It’s one of several that human activities add to the atmosphere. An increase in greenhouse gases leads to greater greenhouse effect. The result is increased global warming. Figure below shows the increase in carbon dioxide since 1960.

What "color" (that is actually not a color at all) is associated with the absence of light?

clear

opaque

grey

black

The color of light that strikes an object may also affect the color that the object appears. For example, if only blue light strikes a red apple, the blue light is absorbed and no light is reflected. When no light reflects from an object, it looks black. Black isn’t a color. It is the absence of light.

What science is the study of matter and how it behaves?

geology

biology

geneology

chemistry

Chemistry is the study of matter and how it behaves.

What do we call the study of life and living things?

physics

chemistry

engineering

life science

Life science is the study of life and living things. Living things are also called organisms . Life science is often referred to as biology. Life scientists work in many different settings, from classrooms to labs to natural habitats. Dr. Katherine Smith, who is pictured in Figure below is a life scientist who works for NOAA (National Oceanic and Atmospheric Administration). She studies freshwater shrimp and fish in their natural habitats.

The average global temperature has been rising since the end of what era?

miocene

glacial

flintstone

pleistocene

The average global temperature has been rising since the end of the Pleistocene. With some ups and downs, of course. Rising temperatures are natural for this time period. But natural causes cannot explain all the warming that's been happening. There is some other factor at work.

What are animals that eat a prey animal?

scavengers

carnivores

herbivores

predators

Predators are animals that eat a prey animal. Scavengers eat organisms that are already dead. Decomposers break down dead plants and animals into component parts, including nutrients.

What are the only decomposers that can break down tough plant substances, including lignin and cellulose?

bacteria

flatworms

insects

fungi

Bacteria are also major decomposers, but they can grow and feed only on the exposed surfaces of organic matter. In contrast, fungi can use their hyphae to penetrate deep into organic matter. Fungi are also the only decomposers that can break down tough plant substances, including lignin (in wood) and cellulose (in plant cell walls). They have special enzymes to do this work. The enzymes are released by the tips of the hyphae. Because of these abilities, fungi are the primary decomposers in forests (see Figure below ).

What type of carbon compound is methane?

alternating compounds

dynamic organic compounds

stable compounds

volatile organic compounds

Volatile organic compounds (VOCs) are carbon compounds, such as methane. VOCs are released by many human activities. Raising livestock, for example, produces a lot of methane.

In diffusion, substances tend to move from an area of high concentration to an area of what kind of concentration?

Increase

drop

rise

low

Diffusion Diffusion is a passive process of transport. A single substance tends to move from an area of high concentration to an area of low concentration until the concentration is equal across a space. You are familiar with diffusion of substances through the air. For example, think about someone opening a bottle of ammonia in a room filled with people. The ammonia gas is at its highest concentration in the bottle; its lowest concentration is at the edges of the room. The ammonia vapor will diffuse, or spread away, from the bottle, and gradually, more and more people will smell the ammonia as it spreads. Materials move within the cell’s cytosol by diffusion, and certain materials move through the plasma membrane by diffusion (Figure 5.8). Diffusion expends no energy. On the contrary, concentration gradients are a form of potential energy, dissipated as the gradient is eliminated.

In what kind of state are particles fixed in place relative to one another?

liquid state

hybrid state

useful state

solid state

In the solid state, particles are fixed in place relative to one another. In the liquid and gas states, individual particles are free to move.

What is defined as the amount of energy needed to increase the temperature of one gram of water by 1°c. one calorie equals 4.184 joules?

fat

weight

sulfur

calorie

A related unit is the calorie. This term arose prior to the establishment of the SI system and is now replaced by the joule in most situations. One calorie is defined as the amount of energy needed to increase the temperature of one gram of water by 1°C. One calorie equals 4.184 joules. Note that this calorie is not exactly the same as the calories listed on food products. One food Calorie (usually written with a capital C) is equal to 1000 “regular” calories. Thus, a 140-Calorie snack can be fully digested to produce 140,000 calories of energy. We will use the SI unit joules in our discussions of heat energy.

About a third of all bacteria in the gut are members of what species?

trematodes

actinomyces

spirochetes

bacteroides

A wide range of friendly bacteria live in the gut. Bacteria begin to populate the human digestive system right after birth. Gut bacteria include Lactobacillus , the bacteria commonly used in probiotic foods such as yogurt, and E. coli bacteria. About a third of all bacteria in the gut are members of the Bacteroides species. Bacteroides are key in helping us digest plant food.

What form of feedback occurs when an accumulation of an end product slows the process that makes that product?

particular feedback

positive feedback

optimal feedback

negative feedback

null

What is the term for a disease in which the immune system makes an inflammatory response to a harmless antigen?

influenza

nausea

diabetes

allergy

An allergy is a disease in which the immune system makes an inflammatory response to a harmless antigen. Any antigen that causes an allergy is called an allergen. Allergens may be inhaled or ingested, or they may come into contact with the skin. Two common causes of allergies are shown in Figure below . Inhaling ragweed pollen may cause coughing and sneezing. Skin contact with oils in poison ivy may cause an itchy rash.

Why is it easier to move boxes on a wheeled dolly than by sliding them?

more total work

starting friction

increase surface tension

rolling friction

Rolling friction is friction that acts on objects when they are rolling over a surface. Rolling friction is much weaker than sliding friction or static friction. This explains why it is much easier to move boxes on a wheeled dolly than by carrying or sliding them. It also explains why most forms of ground transportation use wheels, including cars, 4-wheelers, bicycles, roller skates, and skateboards. Ball bearings are another use of rolling friction (see Figure below ). They allow parts of a wheel or other machine to roll rather than slide over one another.

What is the protein in red blood cells that transports oxygen in the bloodstream?

plasma

rH factor

insulin

hemoglobin

Hemoglobin is a protein in red blood cells that transports oxygen in the bloodstream. Scientists studied hemoglobin simply to learn how it worked. Out of this research came an understanding of how the protein changes shape when oxygen attaches to it. This information was then applied to help patients with sickle cell anemia, a disorder caused by an abnormal hemoglobin structure that makes hemoglobin molecules clump up when oxygen leaves the protein. Basic knowledge of protein structure led to an improved understanding of a wide-spread disease and opened the door for development of treatments.

Space shuttles are reusable vehicles designed to get astronauts where?

distant solar systems

underwater

the 6th dimension

space

Space shuttles are reusable vehicles for American astronauts to get into space.

Specialized peroxisomes called glyoxysomes are found in the fat-storing tissues of what?

chloroplasts

plant stems

plant leaves

plant seeds

null

The nervous system, together with what system, controls all the other organ systems?

limb system

skeletal system

reproductive system

endocrine system

The nervous system, together with the endocrine system, controls all the other organ systems. The nervous system sends one type of signal around the body, and the endocrine system sends another type of signal around the body. The endocrine system makes and releases chemical messenger molecules, or hormones, which tell other body parts that a change or a reaction is necessary. So what type of signal does the nervous system send?.

What is the physical breakdown of chunks of food into smaller pieces?

mechanical catalyst

mechanical accumulation

dissolving

mechanical digestion

Mechanical digestion is the physical breakdown of chunks of food into smaller pieces. This type of digestion takes place mainly in the mouth and stomach.

Technically, which cells are the only autotrophic parts of the plant?

brown

yellow

red

green

null

This is the study of evolutionary history of groups of related organisms?

paleontology

synonymy

phrenology

phylogeny

Phylogeny is the evolutionary history of group of related organisms. It is represented by a phylogenetic tree that shows how species are related to each other through common ancestors. A clade is a group of organisms that includes an ancestor and all of its descendants. It is a phylogenetic classification, based on evolutionary relationships.

What does urine leave the body through?

the vagina

the skin

the intestine

the urethra

process in which urine leaves the body through a sphincter at the end of the urethra.

What phase is pure chlorine present as?

liquid

oil/gas

mist

gas

null

When electrons from two atoms are each attracted to the nucleus of the other atom, what type of bond is formed?

electrochemical bond

hydrogen bond

ionic bond

covalent bond

Covalent bonds form when the electron clouds of two atoms overlap with each other. In a simple H 2 molecule, the single electron in each atom becomes attracted to the nucleus of the other atom in the molecule as the atoms come closer together. Other covalent bonds form in the same way as unpaired electrons from two atoms “match up” to form the bond. In a fluorine atom, there is an unpaired electron in one of the 2p orbitals. When a F 2 molecule forms, the 2p orbitals from each of the two atoms overlap to produce the F−F covalent bond. The overlapping orbitals do not have to be of the same type to form a covalent bond. For example, in a molecule of HF, the 1s orbital of the hydrogen atom overlaps with the 2p orbital of the fluorine atom ( Figure below ):.

Wave cut platforms are level areas formed by what?

glaciers

shock erosion

surge erosion

wave erosion

Wave-cut platforms are level areas formed by wave erosion. Since these platforms are above sea level, it means that either sea level was higher relative or the rock was lower.

Electronegativities are used to determine the polarity of covalent bonds. the polarity of a covalent bond can be judged by determining the difference of the electronegativities of what involved in the covalent bond?

three atoms

seven atoms

six atoms

two atoms

Electronegativities are used to determine the polarity of covalent bonds. The polarity of a covalent bond can be judged by determining the difference of the electronegativities of the two atoms involved in the covalent bond, as summarized in the following table: Electronegativity Difference.

What are the cell walls of fungi made of?

casein

lectin

proteins

chitin

The cell walls of fungi are made of chitin. Chitin is a tough carbohydrate that also makes up the outer skeleton of insects. The cell walls of plants are made of cellulose.

All the water in the open ocean is referred to as what zone, which is further divided by depth?

oceanic

terrestrial

aquatic

pelagic

Other ocean zones are farther from shore in the open ocean. All the water in the open ocean is called the pelagic zone. It is further divided by depth:.

How many embryonic cell layers do flatworms have?

five

two

four

three

Flatworms have three embryonic cell layers. They have a mesoderm layer in addition to ectoderm and endoderm layers. The mesoderm layer allows flatworms to develop muscle tissues so they can move easily over solid surfaces.

When gasoline is burned, what pollutant is produced?

oxygen

methane

fluorocarbons

carbon dioxide

Using gasoline to power automobiles affects the environment. The exhaust fumes from burning gasoline cause air pollution. These pollutants include smog and ground-level ozone. Air pollution is a big problem for cities where large numbers of people drive every day. Burning gasoline also produces carbon dioxide. This is a greenhouse gas and is a cause of global warming. Similar pollutants come from other forms of oil.

What kingdom of organisms is characterized by having sensory organs, movement, and internal digestion?

plants

bacteria

fungi

animals

Animals not only have specialized cells. Most animals also have tissues and organs. In many animals, organs form organ systems, such as a nervous system. Higher levels of organization allow animals to perform many complex functions. What can animals do that most other living things cannot? Most animals share these characteristics: sensory organs , movement , and internal digestion . All of them are illustrated in Figure below .

What is the base numbering system of metric units?

sixes

twos

ones

tens

Metric units use a base numbering system of 10. Thus a centimeter is ten times larger than a millimeter. A decimeter is 10 times larger than a centimeter and a meter is 10 times larger than a decimeter. Thus a meter is 100 times larger than a centimeter and 1000 times larger than a millimeter. Going the other way, one can say that there are 100 cm contained in a meter.

What do fungi lack which makes it impossible for them to use photosynthesis?

roots

ammonia

sodium

chlorophyll

Fungi lack chlorophyll, so they cannot make food by photosynthesis as plants can. Instead, they are heterotrophs, like animals. But they don’t have a mouth or teeth. So how do fungi “eat”? They get their nutrition by absorbing organic compounds from other organisms. The other organisms may be dead or alive, depending on the fungus.

Spicules are most conspicuously present in which class?

trichina

phylum

spirogyra

hexactinellida

Take an up-close tour (http://openstaxcollege. org/l/sponge_ride) through the sponge and its cells. The presence and composition of spicules/spongin are the differentiating characteristics of the three classes of sponges (Figure 28.4): Class Calcarea contains calcium carbonate spicules and no spongin, class Hexactinellida contains six-rayed siliceous spicules and no spongin, and class Demospongia contains spongin and may or may not have spicules; if present, those spicules are siliceous. Spicules are most conspicuously present in class Hexactinellida, the order consisting of glass sponges. Some of the spicules may attain giant proportions (in relation to the typical size range of glass sponges of 3 to 10 mm) as seen in Monorhaphis chuni, which grows up to 3 m long.

Most of the food that they bring to their chicks is very rich in what?

glucose

grains

proteins

lipids

null

Two plates may slide past each other in opposite directions, this is called what?

shearing plate boundary

downstream plate boundary

earthquake

transform plate boundary

Two plates may slide past each other in opposite directions. This is called a transform plate boundary. These plate boundaries experience massive earthquakes. The world’s best known transform fault is the San Andreas Fault in California ( Figure below ). At this fault, the Pacific and North American plates grind past each other. Transform plate boundaries are most common as offsets along mid-ocean ridges.

What term is used to describe elements with unstable nuclei?

waste

explosive

larvae

radioactive

Gamma rays are produced when radioactive elements decay. Radioactive elements are elements with unstable nuclei. To become more stable, the nuclei undergo radioactive decay. In this process, the nuclei give off energy and may also emit charged particles of matter. Types of radioactive decay include alpha, beta, and gamma decay. In alpha and beta decay, both particles and energy are emitted. In gamma decay , only energy, in the form of gamma rays, is emitted.

What is the third gene of lac operon in addition to lacz and lacy?

leya

Lacy

ghara

laca

The three genes of the lac operon are lacZ, lacY, and lacA. They encode proteins needed to digest lactose. The genes are expressed only in the presence of lactose.

The majority of species in the phylum chordata are found in what subphylum, which includes animals ranging from lampreys to mammals?

organelles

lophotrochozoa

tardigrada

vertebrates

Chordates The majority of species in the phylum Chordata are found in the subphylum Vertebrata, which include many species with which we are familiar. The vertebrates contain more than 60,000 described species, divided into major groupings of the lampreys, fishes, amphibians, reptiles, birds, and mammals. Animals in the phylum Chordata share four key features that appear at some stage of their development: a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail (Figure 15.33). In certain groups, some of these traits are present only during embryonic development. The chordates are named for the notochord, which is a flexible, rod-shaped structure that is found in the embryonic stage of all chordates and in the adult stage of some chordate species. It is located between the digestive tube and the nerve cord, and provides skeletal support through the length of the body. In some chordates, the notochord acts as the primary axial support of the body throughout the animal’s lifetime. In vertebrates, the notochord is present during embryonic development, at which time it induces the development of the neural tube and serves as a support for the developing embryonic body. The notochord, however, is not found in the postnatal stage of vertebrates; at this point, it has been replaced by the vertebral column (the spine). The dorsal hollow nerve cord is derived from ectoderm that sinks below the surface of the skin and rolls into a hollow tube during development. In chordates, it is located dorsally to the notochord. In contrast, other animal phyla possess solid nerve cords that are located either ventrally or laterally. The nerve cord found in most chordate embryos develops into the brain and spinal cord, which compose the central nervous system. Pharyngeal slits are openings in the pharynx, the region just posterior to the mouth, that extend to the outside environment. In organisms that live in aquatic environments, pharyngeal slits allow for the exit of water that enters the mouth during feeding. Some invertebrate chordates use the pharyngeal slits to filter food from the water that enters the mouth. In fishes, the pharyngeal slits are modified into gill supports, and in jawed fishes, jaw supports. In tetrapods, the slits are further modified into components of the ear and tonsils, since there is no longer any need for gill supports in these air-breathing.

Why is having grasping hands and feet important for primates?

foraging for food

migrating

protecting habitat

hang on trees

null

The rising and sinking of warm and cooler material is called what?

depression

diffusion

insulation

convection

Hot lower mantle material rises upwards ( Figure below ). As it rises, it cools. At the top of the mantle it moves horizontally. Over time it becomes cool and dense enough that it sinks. Back at the bottom of the mantle, it travels horizontally. Eventually the material gets to the location where warm mantle material is rising. The rising and sinking of warm and cooler material is convection. The motion described creates a convection cell.

What is the remarkable ring of light around the sun called?

laguna

panorama

magnetic halo

corona

A solar eclipse is kind of like a field trip to the Sun from Earth. You can see something (with special tinted glasses) that you don't usually see. The Sun has a remarkable ring of light around it. This is the corona. If you have a chance to see a solar eclipse, you should do it.

Particles in what state of matter do not experience any force of mutual attraction or repulsion?

liquid

plasma

solid

gas

Gas particles do not experience any force of attraction or repulsion with each other.

What is a type of plant tissue consisting of undifferentiated cells that can continue to divide and differentiate?

tuber

malignant

ganglion

meristem

The key to continued growth and repair of plant cells is meristem . Meristem is a type of plant tissue consisting of undifferentiated cells that can continue to divide and differentiate.

What are basic tools of the cell for organizing metabolism, transport, and storage of molecules?

vacuoles

tissues

membranes

vesicles

A vesicle is a small, spherical compartment that is separated from the cytosol by at least one lipid bilayer. Many vesicles are made in the Golgi apparatus and the endoplasmic reticulum, or are made from parts of the cell membrane. Vesicles from the Golgi apparatus can be seen in Figure above . Because it is separated from the cytosol, the space inside the vesicle can be made to be chemically different from the cytosol. Vesicles are basic tools of the cell for organizing metabolism, transport, and storage of molecules. Vesicles are also used as chemical reaction chambers. They can be classified by their contents and function.

The ileum is the last part of what organ, and is where the bile salts and vitamins are absorbed into blood stream?

stomach

large intestine

gall bladder

small intestine

The ileum, also illustrated in Figure 34.11 is the last part of the small intestine and here the bile salts and vitamins are absorbed into blood stream. The undigested food is sent to the colon from the ileum via peristaltic movements of the muscle. The ileum ends and the large intestine begins at the ileocecal valve. The vermiform, “worm-like,” appendix is located at the ileocecal valve. The appendix of humans secretes no enzymes and has an insignificant role in immunity. Large Intestine The large intestine, illustrated in Figure 34.13, reabsorbs the water from the undigested food material and processes the waste material. The human large intestine is much smaller in length compared to the small intestine but larger in diameter. It has three parts: the cecum, the colon, and the rectum. The cecum joins the ileum to the colon and is the receiving pouch for the waste matter. The colon is home to many bacteria or “intestinal flora” that aid in the digestive processes. The colon can be divided into four regions, the ascending colon, the transverse colon, the descending colon and the sigmoid colon. The main functions of the colon are to extract the water and mineral salts from undigested food, and to store waste material. Carnivorous mammals have a shorter large intestine compared to herbivorous mammals due to their diet.

Total internal reflections the princicple behind what type of optics?

Blindness

pipes optics

refined optics

fiber optics

Total internal reflection is the principle behind fiber optics . A bundle of fibers made out of glass or plastic only a few micrometers in diameter is called a light pipe since light can be transmitted along it with almost no loss. Light passing down the fibers makes glancing collisions with the walls so that total internal reflection occurs.

Which cells at the base of the hair root form the outer root sheath?

scala media

scala vestibuli

tunnel fibers

basal

Figure 5.12 Hair Follicle The slide shows a cross-section of a hair follicle. Basal cells of the hair matrix in the center differentiate into cells of the inner root sheath. Basal cells at the base of the hair root form the outer root sheath. LM × 4. (credit: modification of work by “kilbad”/Wikimedia Commons).

What is the term for sediment deposited by a glacier?

plateau

holocene

crater

moraine

Moraine is sediment deposited by a glacier. A ground moraine is a thick layer of sediments left behind by a retreating glacier. An end moraine is a low ridge of sediments deposited at the end of the glacier. It marks the greatest distance the glacier advanced.

Usually done on computers, what do you call sets of equations that take into account many factors to represent a phenomenon?

spreadsheets

fractals

analogous models

mathematical models

Mathematical models are sets of equations that take into account many factors to represent a phenomenon. Mathematical models are usually done on computers.

What is the mode of breathing that occurs at rest and does not require the cognitive thought of the individual?

forced breathing

conscious breathing

small breathing

quiet breathing

There are different types, or modes, of breathing that require a slightly different process to allow inspiration and expiration. Quiet breathing, also known as eupnea, is a mode of breathing that occurs at rest and does not require the cognitive thought of the individual. During quiet breathing, the diaphragm and external intercostals must contract. A deep breath, called diaphragmatic breathing, requires the diaphragm to contract. As the diaphragm relaxes, air passively leaves the lungs. A shallow breath, called costal breathing, requires contraction of the intercostal muscles. As the intercostal muscles relax, air passively leaves the lungs. In contrast, forced breathing, also known as hyperpnea, is a mode of breathing that can occur during exercise or actions that require the active manipulation of breathing, such as singing. During forced breathing, inspiration and expiration both occur due to muscle contractions. In addition to the contraction of the diaphragm and intercostal muscles, other accessory muscles must also contract. During forced inspiration, muscles of the neck, including the scalenes, contract and lift the thoracic wall, increasing lung volume. During forced expiration, accessory muscles of the abdomen, including the obliques, contract, forcing abdominal organs upward against the diaphragm. This helps to push the diaphragm further into the thorax, pushing more air out. In addition, accessory muscles (primarily the internal intercostals) help to compress the rib cage, which also reduces the volume of the thoracic cavity.

Rubber is what kind of solid?

porous

inorganic

aqueous

amorphous

When a tire goes flat, its shape changes. The tire might be flat because of a slow leak in the tire valve. It could be flat because it ran over a nail or screw and ended up with a small hole where the air can leak out over a period of time. Or it could go flat when it hits a large rock or other object while travelling at high speeds (this one is for those readers who enjoy detective movies or TV shows). What if a crystalline solid like LiBr were ever made into a tire (now there’s a weird idea)? When it encountered a blow, the crystal would break into small pieces. Since rubber is an amorphous solid, it has a very different set of physical properties.

What do birds do in mating season?

find many mates

migrate

reproduce asexually

pair up with the same bird

Yes. Birds do actually pair up each mating season, if not for life. And the male better be prepared to treat his female properly. There is actually an elaborate process in which the female chooses her mate.

What exciting and evolving field of physics finds that nature on the smallest scale may have its greatest influence on the large-scale character of the universe?

astrophysics

proteins physics

biophysics

particle physics

This chapter covers the basics of particle physics as we know it today. An amazing convergence of topics is evolving in particle physics. We find that some particles are intimately related to forces, and that nature on the smallest scale may have its greatest influence on the large-scale character of the universe. It is an adventure exceeding the best science fiction because it is not only fantastic, it is real.

In genetics, what does it mean when the amount is longer since the amount of time since a species diverged?

Less difference in DNA

greater making in dna

tilt differences in dna

greater differences in dna

Scientists can compare the DNA or proteins of different species. If the molecules are similar, this shows that the species are related. The more similar the molecules are, the closer the relationship is likely to be. When molecules are used in this way, they are called molecular clocks . This method assumes that random mutations occur at a constant rate for a given protein or segment of DNA. Over time, the mutations add up. The longer the amount of time since species diverged, the more differences there will be in their DNA or proteins.

Ragweed and poison ivy are common causes of what?

defects

cancers

mutations

allergies

Ragweed and poison ivy are common causes of allergies. Are you allergic to these plants?.

What type of distance is caused by the force you apply to a machine over a given distance?

response distance

accumulation distance

force distance

input distance

The force you apply to a machine is applied over a given distance, called the input distance. The force applied by the machine to the object is also applied over a distance, called the output distance. The output distance may or may not be the same as the input distance.

What is calculated by dividing the mass by the volume of a certain object?

median

radius

diameter

density

The density of a certain object is calculated by dividing the mass by the volume. Suppose that a mass of 37.46 g is divided by a volume of 12.7 cm 3 . The result on a calculator would be:.

Electric motors transform electrical energy into what other form of energy?

solar

magnetic

thermal

kinetic

An electric motor is a device that uses an electromagnet to change electrical energy to kinetic energy. Figure below shows a simple diagram of an electric motor. The motor contains an electromagnet that is connected to a shaft. When current flows through the motor, the electromagnet turns, causing the shaft to turn as well. The rotating shaft moves other parts of the device.

The bicoid maternal effect gene is transcribed in which cells of the mother?

cell walls

veteran cells

boy cells

nurse cells

The bicoid maternal effect gene is transcribed in the nurse cells of the mother and then the mRNA is transferred to the oocyte. Mutant embryos from homozygous mutant bicoid mothers fail to produce head and thorax structures.

How often an allele occurs in a gene pool relative to the other alleles for that gene is known as _______

genetic rate

allele succession

genomic frequency

allele frequency

Allele frequency is how often an allele occurs in a gene pool relative to the other alleles for that gene. Look at the example in Table below . The population in the table has 100 members. In a sexually reproducing species, each member of the population has two copies of each gene. Therefore, the total number of copies of each gene in the gene pool is 200. The gene in the example exists in the gene pool in two forms, alleles A and a . Knowing the genotypes of each population member, we can count the number of alleles of each type in the gene pool. The table shows how this is done.

If more coils are added to an electromagnet it becomes?

brighter

lighter

weaker

stronger

The combined magnetic force of the magnetized wire coil and iron bar makes an electromagnet very strong. In fact, electromagnets are the strongest magnets made. An electromagnet is stronger if there are more turns in the coil of wire or there is more current flowing through it. A bigger bar or one made of material that is easier to magnetize also increases an electromagnet’s strength. At the following URL, you can see an animation demonstrating how these factors affect the strength of an electromagnet. http://www. schoolphysics. co. uk/animations/Electromagnet/index. html.