NilsML/retriever_dataset · Datasets at Hugging Face

question stringlengths 14 399	distractor3 stringlengths 1 63	distractor1 stringlengths 1 57	distractor2 stringlengths 1 62	correct_answer stringlengths 1 67	support stringlengths 31 3.56k ⌀
Science works hand in hand with what for the advancement of both?	banks	industry	government	technology	Although they have different goals, technology and science work hand in hand. Each helps the other advance. Scientific knowledge is needed to create new technologies. New technologies are used to further science. The microscope is a good example. Scientific knowledge of light allowed 17 th century lens makers to make the first microscopes. This new technology let scientists view a world of tiny objects they had never before seen. Figure below describes other examples.
Which part of the brain is responsible for working memory?	brain stem	amygdala	cerebellum	prefrontal cortex	14.3 Motor Responses The motor components of the somatic nervous system begin with the frontal lobe of the brain, where the prefrontal cortex is responsible for higher functions such as working memory. The integrative and associate functions of the prefrontal lobe feed into the secondary motor areas, which help plan movements. The premotor cortex and supplemental motor area then feed into the primary motor cortex that initiates movements. Large Betz cells project through the corticobulbar and corticospinal tracts to synapse on lower motor neurons in the brain stem and ventral horn of the spinal cord, respectively. These connections are responsible for generating movements of skeletal muscles. The extrapyramidal system includes projections from the brain stem and higher centers that influence movement, mostly to maintain balance and posture, as well as to maintain muscle tone. The superior colliculus and red nucleus in the midbrain, the vestibular nuclei in the medulla, and the reticular formation throughout the brain stem each have tracts projecting to the spinal cord in this system. Descending input from the secondary motor cortices, basal nuclei, and cerebellum connect to the origins of these tracts in the brain stem. All of these motor pathways project to the spinal cord to synapse with motor neurons in the ventral horn of the spinal cord. These lower motor neurons are the cells that connect to skeletal muscle and cause contractions. These neurons project through the spinal nerves to connect to the muscles at neuromuscular junctions. One motor neuron connects to multiple muscle fibers within a target muscle. The number of fibers that are innervated by a single motor neuron varies on the basis of the precision necessary for that muscle and the amount of force necessary for that motor unit. The quadriceps, for example, have many fibers controlled by single motor neurons for powerful contractions that do not need to be precise. The extraocular muscles have only a small number of fibers controlled by each motor neuron because moving the eyes does not require much force, but needs to be very precise. Reflexes are the simplest circuits within the somatic nervous system. A withdrawal reflex from a painful stimulus only requires the sensory fiber that enters the spinal cord and the motor neuron that projects to a muscle. Antagonist and postural muscles can be coordinated with the withdrawal, making the connections more complex. The simple, single neuronal.
What are bundles of collecting ducts that transport urine made by nephrons to the calyces of the kidney for excretion?	cuticle	cartoid	esophagus	papillae	Internal Anatomy A frontal section through the kidney reveals an outer region called the renal cortex and an inner region called the medulla (Figure 25.8). The renal columns are connective tissue extensions that radiate downward from the cortex through the medulla to separate the most characteristic features of the medulla, the renal pyramids and renal papillae. The papillae are bundles of collecting ducts that transport urine made by nephrons to the calyces of the kidney for excretion. The renal columns also serve to divide the kidney into 6–8 lobes and provide a supportive framework for vessels that enter and exit the cortex. The pyramids and renal columns taken together constitute the kidney lobes.
What do snakes use to smell things?	their nose	their mouth	their eyes	their tongue	Most reptiles have good eyesight and a keen sense of smell. Snakes smell scents in the air using their forked tongue (see Figure below ). This helps them locate prey. Some snakes have heat-sensing organs on their head that help them find endothermic prey, such as small mammals and birds.
Cardiac muscle normally has what kind of oxygen-using metabolism?	anarobic	digestive	glucose	aerobic	Cardiac Muscle Metabolism Normally, cardiac muscle metabolism is entirely aerobic. Oxygen from the lungs is brought to the heart, and every other organ, attached to the hemoglobin molecules within the erythrocytes. Heart cells also store appreciable amounts of oxygen in myoglobin. Normally, these two mechanisms, circulating oxygen and oxygen attached to myoglobin, can supply sufficient oxygen to the heart, even during peak performance. Fatty acids and glucose from the circulation are broken down within the mitochondria to release energy in the form of ATP. Both fatty acid droplets and glycogen are stored within the sarcoplasm and provide additional nutrient supply. (Seek additional content for more detail about metabolism.
Burning fossil fuels releases what into the atmosphere?	nitrogen dioxide	carbon monoxide	phosphorus dioxide	carbon dioxide	Burning organic material, such as fossil fuels, releases carbon dioxide.
Cnidarians are an ancient phylum of what?	arthropods	sporozoans	fungi	eumetazoans	33.2 Cnidarians are an ancient phylum of eumetazoans.
What theory states that both energy and matter have characteristics of waves under some conditions and characteristics of particles under other conditions?	atomic theory	static theory	big bang theory	quantum theory	Most definitions of quantum theory and quantum mechanics offer the same description for both. These definitions essentially describe quantum theory as a theory in which both energy and matter have characteristics of waves under some conditions and characteristics of particles under other conditions.
At which location is the earth hottest?	meridian	desert	seabed	equator	Earth is hottest at the Equator and gets cooler toward the poles. The differences in heating create huge convection currents in the troposphere. At the Equator, for example, warm air rises up to the tropopause. When it can’t rise any higher, it flows north or south.
What is process of producing eggs in the ovary called?	vaginalis	menstruation	morphogenesis	oogenesis	The process of producing eggs in the ovary is called oogenesis . Eggs, like sperm, are haploid cells, and their production occurs in several steps that involve different types of cells, as shown in Figure below . You can follow the process of oogenesis in the figure as you read about it below.
What protein is hair mostly made of?	Actin	coronin	Dystrophin	keratin	null
What is it called when the vesicle and target membrane fuse?	pathogen fusion	tendon fusion	enamel fusion	vesicle fusion	For a vesicle to release its contents to a cell organelle or to the outside of the cell, the vesicle and target membrane must fuse. This process is called vesicle fusion. Fusion between the vesicle and a target membrane occurs in one of two ways: full fusion or "kiss-and-run" fusion. In a full fusion process, the vesicle phospholipids fully incorporate into the plasma membrane. The vesicle can only be reformed and by a clathrin-coat-dependent process. With kiss-and-run fusion, the vesicle reforms after the release of its material. This allows the rapid release of materials from a synaptic vesicle. In this type of fusion, the vesicle forms a fusion pore or porosome in the presynaptic membrane and releases its neurotransmitters across the synapse, after which the vesicle reforms, allowing it to be reused.
What is the term for the number of covalent bonds an atom can form?	covalent number	atomic number	gradient	valence	null
Momentum can be expressed as the product of mass and what else?	acceleration	density	direction	velocity	If a bowling ball and a ping-pong ball are each moving with a velocity of 5 mph, you intuitively understand that it will require more effort to stop the bowling ball than the ping pong ball because of the greater mass of the bowling ball. Similarly, if you have two bowling balls, one moving at 5 mph and the other moving at 10 mph, you know it will take more effort to stop the ball with the greater speed. It is clear that both the mass and the velocity of a moving object contribute to what is necessary to change the motion of the moving object. The product of the mass and velocity of an object is called its momentum . Momentum is a vector quantity that has the same direction as the velocity of the object and is represented by a lowercase letter p .
A carbon atom with 6 protons and 8 neutrons is more specifically known as?	carbon 6	carbon 12	carbon 8	carbon 14	An example of a radioisotope is carbon-14. All carbon atoms have 6 protons, and most have 6 neutrons. These carbon atoms are called carbon-12, where 12 is the mass number (6 protons + 6 neutrons). A tiny percentage of carbon atoms have 8 neutrons instead of the usual 6. These atoms are called carbon-14 (6 protons + 8 neutrons). The nuclei of carbon-14 are unstable because they have too many neutrons. To be stable, a small nucleus like carbon, with just 6 protons, must have a 1:1 ratio of protons to neutrons. In other words, it must have the same number of neutrons as protons. In a large nucleus, with many protons, the ratio must be 2:1 or even 3:1 protons to neutrons.
Who was the first person known to use a telescope to study the sky?	Einstein	Copernicus	darwin	galileo	Galileo was the first person known to use a telescope to study the sky. His discoveries helped change the way humans think about the universe.
What kind of decay is electron capture a type of?	alpha decay	gamma decay	gradual decay	beta decay	since we use the masses of neutral atoms. Electron capture is the third type of beta decay. Here, a nucleus captures an inner-shell electron and undergoes a nuclear + reaction that has the same effect as β decay. Electron capture is sometimes denoted by the letters EC. We know that electrons cannot reside in the nucleus, but this is a nuclear reaction that consumes the electron and occurs spontaneously only when the products have less mass than the parent plus the electron. If a nuclide ZA X N is known to undergo electron capture, then its electron capture equation is A Z XN.
What is the result of a reaction between sulfur trioxide and water?	hydrochloric acid	nitric acid	acetic acid	sulfuric acid	Sulfur trioxide gas reacts with water to form sulfuric acid. This is an unfortunately common reaction that occurs in the atmosphere in some places where oxides of sulfur are present as pollutants. The acid formed in the reaction falls to the ground as acid rain.
Fragmentation with subsequent regeneration is a method of what, exhibited by animals such as sea stars?	microscopic reproduction	sexual reproduction	bacteria reproduction	asexual reproduction	Watch a video (http://openstaxcollege. org/l/budding_hydra) of a hydra budding. Fragmentation Fragmentation is the breaking of the body into two parts with subsequent regeneration. If the animal is capable of fragmentation, and the part is big enough, a separate individual will regrow. For example, in many sea stars, asexual reproduction is accomplished by fragmentation. Figure 43.4 illustrates a sea star for which an arm of the individual is broken off and regenerates a new sea star. Fisheries workers have been known to try to kill the sea stars eating their clam or oyster beds by cutting them in half and throwing them back into the ocean. Unfortunately for the workers, the two parts can each regenerate a new half, resulting in twice as many sea stars to prey upon the oysters and clams. Fragmentation also occurs in annelid worms, turbellarians, and poriferans.
What happens to atoms during a substitution reaction?	disintegrate	impaction	fusion	replace another in a molecule	A substitution reaction is a reaction in which one or more atoms replace another atom or group of atoms in a molecule. Alkyl halides are formed by the substitution of a halogen atom for a hydrogen atom. When methane reacts with chlorine gas, ultraviolet light can act as a catalyst for the reaction.
What lines the lungs and helps sweep mucus and pathogens out of the lungs?	villi	actin	alveoli	cilia	Charles Daghlian. Cilia lining the lungs help sweep mucus and pathogens out of the lungs . Public Domain.
Because most gas particles in the atmosphere are concentrated close to earth's surface, air pressure is greatest where?	atmosphere	ground level	seabed floor	at sea level	We live in a “sea” of air called the atmosphere. Can you feel the air in the atmosphere pressing against you? Not usually, but air actually exerts a lot of pressure because there’s so much of it. The atmosphere rises high above Earth’s surface, so it contains a huge number of gas particles. Most of them are concentrated close to Earth’s surface because of gravity and the weight of all the air in the atmosphere above them. As a result, air pressure is greatest at sea level and drops rapidly as you go higher in altitude. The Figure below shows how air pressure falls from sea level to the top of the atmosphere. In the graph, air pressure is measured in a unit called the millibar (mb). The SI unit of pressure is newton per square centimeter (N/cm 2 ).
Control rods containing nuclides that very strongly absorb neutrons are used to adjust what?	thermal flux	nuclei flux	fission flux	neutron flux	Control rods containing nuclides that very strongly absorb neutrons are used to adjust neutron flux. To produce large power, reactors contain hundreds to thousands of critical masses, and the chain reaction easily becomes self-sustaining, a condition called criticality. Neutron flux should be carefully regulated to avoid an exponential increase in fissions, a condition called supercriticality. Control rods help prevent overheating, perhaps even a meltdown or explosive disassembly. The water that is 235 used to thermalize neutrons, necessary to get them to induce fission in U , and achieve criticality, provides a negative.
All radioactive nuclides emit high-energy particles or what?	isotopes	magnetic fields	thermal energy	electromagnetic waves	The increased use of radioisotopes has led to increased concerns over the effects of these materials on biological systems (such as humans). All radioactive nuclides emit high-energy particles or electromagnetic waves. When this radiation encounters living cells, it can cause heating, break chemical bonds, or ionize molecules. The most serious biological damage results when these radioactive emissions fragment or ionize molecules. For example, alpha and beta particles emitted from nuclear decay reactions possess much higher energies than ordinary chemical bond energies. When these particles strike and penetrate matter, they produce ions and molecular fragments that are extremely reactive. The damage this does to biomolecules in living organisms can cause serious malfunctions in normal cell processes, taxing the organism’s repair mechanisms and possibly causing illness or even death (Figure 21.30).
What process is the synthesis of glucose from pyruvate, lactate and glycerol?	photosynthesis	hydrolysis	glycolysis	gluconeogenesis	Gluconeogenesis is the synthesis of glucose from pyruvate, lactate, glycerol,.
What is the creation of a new species called?	mutation	evolution	synthesis	speciation	The creation of a new species is called speciation . Most new species develop naturally. But humans have also artificially created new breeds and species for thousands of years.
What do humans use to make observations?	nutrients	hormones	blood	senses	Make observations. Observations refer to anything detected with one or more senses. The senses include sight, hearing, touch, smell, and taste.
The human penis contains the urethra, as well as how many cylinders of spongy erectile tissue?	five	Zero	nine	three	null
When water freezes, it expands in volume as what is formed?	energy	movement	plasma	ice	Ice is an interesting and useful material. It can be used to cool food and keep it fresh. It can provide recreation, such as ice-skating. Ice can do great damage when it freezes – roads can buckle, houses can be damaged, water pipes can burst. All this happens because of a unique property of water and ice. When water freezes, it expands in volume as ice is formed.
What is a substance or object that absorbs and dissipates heat but does not experience a corresponding increase in temperature?	heat dispeller	heat diffuser	heat storer	heat sink	Water as a Heat Sink A heat sink is a substance or object that absorbs and dissipates heat but does not experience a corresponding increase in temperature. In the body, water absorbs the heat generated by chemical reactions without greatly increasing in temperature. Moreover, when the environmental temperature soars, the water stored in the body helps keep the body cool. This cooling effect happens as warm blood from the body’s core flows to the blood vessels just under the skin and is transferred to the environment. At the same time, sweat glands release warm water in sweat. As the water evaporates into the air, it carries away heat, and then the cooler blood from the periphery circulates back to the body core.
Vesicles can be classified by their contents and what else?	color	example	smell	function	Vesicles can be classified by their contents and function.
The main function of this organ is to filter the blood and remove unwanted red blood cells?	heart	pancreas	kidney	spleen	Organs of the lymphatic system include the tonsils, thymus gland and spleen. The thymus gland produces T cells or T-lymphocytes (see below) and the spleen and tonsils help in fighting infections. The spleen’s main function is to filter the blood, removing unwanted red blood cells. The spleen also detects viruses and bacteria and triggers the release of pathogen fighting cells.
The brain case consists of eight bones which include the paired parietal and temporal bones, plus the unpaired frontal, occipital, sphenoid, and which other bone?	posterior	altoid	perpendicular	ethmoid	The brain case consists of eight bones. These include the paired parietal and temporal bones, plus the unpaired frontal, occipital, sphenoid, and ethmoid bones.
What can have complex effects on soil nutrient concentrations?	eukaryotes	the sun	sediments	prokaryotes	null
Rems, rads, and curies are all used to measure what?	thermal energy	gravity	potential energy	radioactivity	Radioactivity can be expressed in a variety of units, including rems, rads, and curies.
What governs motions of stars, galaxies and other celestial objects orbiting one another?	magnetic force	electrical force	frictional force	gravitational force	6.6 Satellites and Kepler’s Laws: An Argument for Simplicity Examples of gravitational orbits abound. Hundreds of artificial satellites orbit Earth together with thousands of pieces of debris. The Moon’s orbit about Earth has intrigued humans from time immemorial. The orbits of planets, asteroids, meteors, and comets about the Sun are no less interesting. If we look further, we see almost unimaginable numbers of stars, galaxies, and other celestial objects orbiting one another and interacting through gravity. All these motions are governed by gravitational force, and it is possible to describe them to various degrees of precision. Precise descriptions of complex systems must be made with large computers. However, we can describe an important class of orbits without the use of computers, and we shall find it instructive to study them. These orbits have the following characteristics: 1. A small mass.
The numbers and types of species living in what groups generally change through time, a process called ecological succession?	biospheres	movements	regions	communities	Communities are not usually static. The numbers and types of species that live in them generally change through time. This is called ecological succession . Important cases of succession are primary and secondary succession.
Claw hammers and pulleys are examples of simple machines that do what to the direction of force applied by the user?	nothing	neutralize it	maintain it	reverse it	Some machines change the direction of the force applied by the user. They may or may not also change the strength of the force or the distance over which it is applied. Two examples of machines that work in this way are claw hammers and the rope systems (pulleys) that raise or lower flags on flagpoles. Figure below explains how these machines work. In each case, the direction of the force applied by the user is reversed by the machine. How does this make it easier to do the job?.
A circular coral reef could indicate the earlier existence of what?	tsunami	landslide	avalanche	volcano	Reefs can form interesting shapes in the oceans. Remember that there are many volcanoes in the ocean. Coral reefs can form on volcanoes in tropical water. Since the volcanoes are cones, the reef forms in a circle around the volcano. Eventually the volcano becomes inactive. The mountain subsides and erodes so that it is below sea level. This leaves a circular coral reef ( Figure below ).
Many fungi protect themselves from parasites and predators by producing what?	pheromes	gaseous chemicals	ammonia	toxic chemicals	Many fungi protect themselves from parasites and predators by producing toxic chemicals. If people eat toxic fungi, they may experience digestive problems, hallucinations, organ failure, and even death. Most cases of mushroom poisoning are due to mistaken identity. That’s because many toxic mushrooms look very similar to safe, edible mushrooms. An example is shown in Figure below .
Acid rain falling in lakes can kill aquatic organisms by lowering what?	food level	color level	saliva level	ph level	If acid rain falls into lakes, it lowers the pH of the water and may kill aquatic organisms. If it falls on the ground, it may damage soil and soil organisms. If it falls on plants, it may make them sick or even kill them. Acid rain also damages stone buildings, bridges, and statues, like the one in Figure below .
What do plant and fungi cells have that animal cells lack?	cell swamps	cell holes	cell ridges	cell walls	null
Which type of energy holds atoms together?	curve energy	atomic energy	nuclear energy	bond energy	Atoms are held together by a certain amount of energy called bond energy.
What type of energy is the energy stored in an object due to its position?	directional energy	spontaneous energy	mechanical energy	potential energy	Potential energy is the energy stored in an object due to its position. A bouncing ball at the top of a bounce, just before it starts to fall, has potential energy. For that instant, the ball is not moving, but it has the potential to move because gravity is pulling on it. Once the ball starts to fall, the potential energy changes to kinetic energy. When the ball hits the ground, it gains potential energy from the impact. The potential energy changes to kinetic energy when the ball bounces back up into the air. As the ball gains height, it regains potential energy because of gravity.
What is the amount of product that may be produced by a reaction under specified conditions called?	reactant	solute	catalytic yield	theoretical yield	Percent Yield The amount of product that may be produced by a reaction under specified conditions, as calculated per the stoichiometry of an appropriate balanced chemical equation, is called the theoretical yield of the reaction. In practice, the amount of product obtained is called the actual yield, and it is often less than the theoretical yield for a number of reasons. Some reactions are inherently inefficient, being accompanied by side reactions that generate other products. Others are, by nature, incomplete (consider the partial reactions of weak acids and bases discussed earlier in this chapter). Some products are difficult to collect without some loss, and so less than perfect recovery will reduce the actual yield. The extent to which a reaction’s theoretical yield is achieved is commonly expressed as its percent yield: percent yield =.
Sometimes referred to as air, what do we call the mixture of gases that surrounds the planet?	hemisphere	outer space	galaxy	atmosphere	Why is Earth the only planet in the solar system known to have life? The main reason is Earth’s atmosphere. The atmosphere is a mixture of gases that surrounds the planet. We also call it air. The gases in the air include nitrogen, oxygen, and carbon dioxide. Along with water vapor, air allows life to survive. Without it, Earth would be a harsh, barren world.
What is another term for seed plants?	petals	stems	sporozoans	spermatophytes	Most vascular plants are seed plants, or spermatophytes. They reproduce with seeds and pollen.
Kinetic theory is the atomistic description of what as well as liquids and solids?	fluids	plasmas	molecules	gases	13.4 Kinetic Theory: Atomic and Molecular Explanation of Pressure and Temperature • Kinetic theory is the atomistic description of gases as well as liquids and solids. • Kinetic theory models the properties of matter in terms of continuous random motion of atoms and molecules. • The ideal gas law can also be expressed as.
Though it can change states, and it often does, what cannot be created or destroyed?	volums	mass	water content	matter	Then, the muscles of the uterus start contracting. The contractions get stronger and closer together. They may go on for hours. Eventually, the contractions squeeze the baby out of the uterus. Once the baby enters the vagina, the mother starts pushing. She soon pushes the baby through the vagina and out of her body.
What are the long carbon chains that make up lipids?	nucleic acids	proteins	carbohydrates	fatty acids	Lipids are made up of long carbon chains called fatty acids. Like hydrocarbons, fatty acids may be saturated or unsaturated. Figure below shows structural formulas for two small fatty acids. One is saturated and one is unsaturated.
As the anterior end of the neural tube starts to develop into the brain, it undergoes a couple of enlargements; the result is the production of these?	tributaries - like vesicles	cyclinder-like vesicles	square-like vesicles	sac-like vesicles	Primary Vesicles As the anterior end of the neural tube starts to develop into the brain, it undergoes a couple of enlargements; the result is the production of sac-like vesicles. Similar to a child’s balloon animal, the long, straight neural tube begins to take on a new shape. Three vesicles form at the first stage, which are called primary vesicles. These vesicles are given names that are based on Greek words, the main root word being enkephalon, which means “brain” (en- = “inside”; kephalon = “head”). The prefix to each generally corresponds to its position along the length of the developing nervous system. The prosencephalon (pros- = “in front”) is the forward-most vesicle, and the term can be loosely translated to mean forebrain. The mesencephalon (mes- = “middle”) is the next vesicle, which can be called the midbrain. The third vesicle at this stage is the rhombencephalon. The first part of this word is also the root of the word rhombus, which is a geometrical figure with four sides of equal length (a square is a rhombus with 90° angles). Whereas prosencephalon and mesencephalon translate into the English words forebrain and midbrain, there is not a word for “four-sided-figure-brain. ” However, the third vesicle can be called the hindbrain. One way of thinking about how the brain is arranged is to use these three regions—forebrain, midbrain, and hindbrain—which are based on the primary vesicle stage of development (Figure 13.3a).
What makes the sun glow brightly?	sun bursts	radiation	ultraviolet rays	nuclear fusion	What causes the sun to glow so brightly? The answer is nuclear fusion. Nuclear fusion is a type of nuclear reaction, and it releases a huge amount of energy.
Lens faces can generally either be concave, or what, which is the opposite of concave?	spherical	hollow	elliptical	convex	One or both of the lens faces is part of a sphere and can be concave or convex.
Part of the fossil record, stromatolites belong to what rock group and are formed when minerals are precipitated out of water by prokaryotes in a microbial mat?	crystalline	metamorphic	igneous	sedimentary	Stromatolites Fossilized microbial mats represent the earliest record of life on Earth. A stromatolite is a sedimentary structure formed when minerals are precipitated out of water by prokaryotes in a microbial mat (Figure 22.3). Stromatolites form layered rocks made of carbonate or silicate. Although most stromatolites are artifacts from the past, there are places on Earth where stromatolites are still forming. For example, growing stromatolites have been found in the Anza-Borrego Desert State Park in San Diego County, California.
Vinegar is an example of what type of acid?	carbonic	ascorbic	acetic	carboxylic	Carboxylic acid is a carbonyl in which in which the carbon atom is bonded to an OH group on one side and either a carbon or hydrogen atom on the other. Carboxylic acids are weak acids, for example, vinegar.
What system of the body is most involved in the immune response?	anomalous system	primordial system	circulatory system	lymphatic system	The immune response mainly involves the lymphatic system. The lymphatic system is a major part of the immune system. It produces leukocytes called lymphocytes. Lymphocytes are the key cells involved in the immune response. They recognize and help destroy particular pathogens in body fluids and cells. They also destroy certain cancer cells.
The highest level of organization in ecology is known as what?	reserves	topmast	preserves	biosphere	The biosphere consists of all the parts of Earth where life can be found. This is the highest level of organization in ecology. It includes all of the other levels below it. The biosphere consists of all the world’s biomes, both terrestrial and aquatic.
Food allergies, ulcers, and heartburn are diseases of what system of the body?	skeletal system	nervous system	circulatory system	digestive system	Digestive system diseases include food allergies, ulcers, and heartburn.
Bases turn red litmus paper which color?	white	pink	white	blue	Indicator compounds such as litmus can be used to detect bases. Bases turn red litmus paper blue.
What two elements do ribosome consist of?	malassezia and proteins	lafleur and proteins	dna	rrna and proteins	The ribosome consists of rRNA and proteins. It reads the sequence of codons in mRNA.
What is the term for the flow of charge that a voltage source creates?	velocity	force	output	current	measured at various points in a circuit, it will be seen to increase at the voltage source and decrease at the resistor. Voltage is similar to fluid pressure. The voltage source is like a pump, creating a pressure difference, causing current—the flow of charge. The resistor is like a pipe that reduces pressure and limits flow because of its resistance. Conservation of energy has important consequences here. The voltage source supplies energy (causing an electric field and a current), and the resistor converts it to another form (such as thermal energy). In a simple circuit (one with a single simple resistor), the voltage supplied by the source equals the voltage drop across the resistor, since PE = qΔV , and the same q flows through each. Thus the energy supplied by the voltage source and the energy converted by the resistor are equal. (See Figure 20.9.
What happens to a cell's efficiency as it grows in size?	multiplies	increases	splits in half	decreases	Small size, in general, is necessary for all cells, whether prokaryotic or eukaryotic. Let’s examine why that is so. First, we’ll consider the area and volume of a typical cell. Not all cells are spherical in shape, but most tend to approximate a sphere. You may remember from your high school geometry course that the formula for the surface area of a sphere is 4πr2, while the formula for its volume is 4πr3/3. Thus, as the radius of a cell increases, its surface area increases as the square of its radius, but its volume increases as the cube of its radius (much more rapidly). Therefore, as a cell increases in size, its surface area-to-volume ratio decreases. This same principle would apply if the cell had the shape of a cube (Figure 4.7). If the cell grows too large, the plasma membrane will not have sufficient surface area to support the rate of diffusion required for the increased volume. In other words, as a cell grows, it becomes less efficient. One way to become more efficient is to divide; another way is to develop organelles that perform specific tasks. These adaptations lead to the development of more sophisticated cells called eukaryotic cells.
What is responsible not only for cell shape changes but also for cell migration?	cellulose	Golgi Apparatus	cytoplasm	cytoskeleton	null
What is performed to identify disease-causing genes?	ultrasound	bioremediation	inoculation	genetic testing	CHAPTER SUMMARY 17.1 Biotechnology Nucleic acids can be isolated from cells for the purposes of further analysis by breaking open the cells and enzymatically destroying all other major macromolecules. Fragmented or whole chromosomes can be separated on the basis of size by gel electrophoresis. Short stretches of DNA or RNA can be amplified by PCR. Southern and northern blotting can be used to detect the presence of specific short sequences in a DNA or RNA sample. The term “cloning” may refer to cloning small DNA fragments (molecular cloning), cloning cell populations (cellular cloning), or cloning entire organisms (reproductive cloning). Genetic testing is performed to identify disease-causing genes, and gene therapy is used to cure an inheritable disease. Transgenic organisms possess DNA from a different species, usually generated by molecular cloning techniques. Vaccines, antibiotics, and hormones are examples of products obtained by recombinant DNA technology. Transgenic plants are usually created to improve characteristics of crop plants.
What type of fossils are useful for determining the ages of rock layers?	trace fossils	cast fossils	mold fossils	index fossils	Fossils are the best form of evidence about the history of life on Earth. Fossils also give us clues about major geological events and past climates. Index fossils are useful for determining the ages of rock layers.
What type of organisms carry out their life processes through division of labor and have specialized cells that do specific job?	CompoundCellular	dermal	biomolecular	multicellular	Multicellular organisms carry out their life processes through division of labor. They have specialized cells that do specific jobs.
What defines the behavior of a compound?	location of atoms	size of atoms	area of atoms	group of atoms	In a compound, a group of atoms that define the behavior of the compound.
What collect sunlight on the roof of a house for energy?	asphalt shingles	infrared panels	clay tiles	solar panels	Solar panels collect sunlight on the roof of this house. The energy can be used to run the household.
The light reactions are the steps of photosynthesis that convert solar energy to what other type of energy?	radiation energy	kinetic energy	carbon energy	chemical energy	null
Water waves act as a mix of longitudinal and what other kind of wave?	variable wave	lateral wave	latitudinal	transverse wave	Water waves act as a mix of longitudinal and transverse waves. A typical water molecule pretty much moves in a circle when a wave passes through it.
What is the name for a fertilized cell that results from the uniting of two gametes?	sperm	chromosomes	eggs	zygote	Sexual reproduction involves two parents. As you can see from Figure below , in sexual reproduction, parents produce reproductive cells—called gametes —that unite to form an offspring. Gametes are haploid cells. This means they contain only half the number of chromosomes found in other cells of the organism. Gametes are produced by a type of cell division called meiosis , which is described in detail in a subsequent concept. The process in which two gametes unite is called fertilization . The fertilized cell that results is referred to as a zygote . A zygote is diploid cell, which means that it has twice the number of chromosomes as a gamete.
Caffeine and alcohol are two examples of what type of drug?	psilopsybin	nicotine	barbiturate	psychoactive	Drugs are chemicals that affect the body’s structure or function. Psychoactive drugs, such as caffeine and alcohol, affect the central nervous system by influencing the transmission of nerve impulses in the brain. Psychoactive drugs may be abused and lead to drug addiction.
By maintaining a relatively constant internal environment even when the external environment changes significantly, an animal achieves what?	eternal youth	hibernation	consciousness	homeostasis	null
What is the sticky, moist substance that covers mucous membranes called?	pus	saliva	phlegm	mucus	One defense of mucous membranes is the mucus they release. Mucus is a sticky, moist substance that covers mucous membranes. Most pathogens get stuck in the mucus before they can do harm to the body. Many mucous membranes also have cilia. Cilia in the lungs are pictured below ( Figure below ). Cilia are tiny finger-like projections. They move in waves and sweep mucus and trapped pathogens toward body openings. When you clear your throat or blow your nose, you remove mucus and pathogens from your body.
Most receptors in the dermis are encapsulated by what?	pathogenic tissue	tendons	bone tissue	connective tissue	null
The length of the route between two points is known as what?	shape	velocity	direction	distance	Distance is the length of the route between two points.
How did seismologists originally measure the intensity of an earthquake?	regolith scale	richter scale	Maxwell scale	mercalli scale	The ways seismologists measure an earthquake have changed over the decades. Initially, they could only measure what people felt and saw: the intensity. For this, they used the Mercalli scale.
What is the term for the distance that sound waves travel in a given amount of time?	sonic speed	velocity of sound	sound barrier	speed of sound	The speed of sound is the distance that sound waves travel in a given amount of time. You’ll often see the speed of sound given as 343 meters per second. But that’s just the speed of sound under a certain set of conditions, specifically, through dry air at 20 °C. The speed of sound may be very different through other matter or at other temperatures.
How much of its alleles does a plant pass on when it reproduces sexually?	all	a quarter	none	half	null
Using less energy or using energy more efficiently are the basic methods of what?	pressure conservation	demand conservation	moral conservation	energy conservation	There are two basic ways to conserve energy. You can use less energy. You can also use energy more efficiently.
What will a fertilized ovule develop into?	a gonad	a spore	a spermazoa	a seed	null
What type of particles do acids release, by definition?	fission ions	quarks	nucleic acids	hydrogen ions	Acids are molecular compounds that release hydrogen ions.
An alpha particle, which is relatively large and easily stopped by matter, is a type of what?	free emission	waste emission	plant emission	radioactive emission	Alpha, beta, and gamma emissions have different abilities to penetrate matter. The relatively large alpha particle is easily stopped by matter (although it may impart a significant amount of energy to the matter it contacts). Beta particles penetrate slightly into matter, perhaps a few centimeters at most. Gamma rays can penetrate deeply into matter and can impart a large amount of energy into the surrounding matter. Table 11.1 "The Three Main Forms of Radioactive Emissions" summarizes the properties of the three main types of radioactive emissions. Table 11.1 The Three Main Forms of Radioactive Emissions.
What does antifreeze do to the boiling point of coolant?	has no effect	lowers it	accelerates it	raises it	Flickr: EvelynGiggles, modified by CK-12 Foundation. Antifreeze raises the boiling point of coolant . CC BY 2.0.
What are rhythmic, involuntary contractions of the reproductive structures?	seizure	reproductive spasms	sexual paroxysms	orgasm	null
What happens when oppositely charged regions of neighboring water molecules are attracted to each other?	oxygen is released	potassium bonds form	metabolic bonds form	hydrogen bonds form	null
What occurs when the vapor pressure of a liquid is equal to the atmospheric pressure?	evaporation	freezing	melting	boiling	Recall that boiling occurs when the vapor pressure of a liquid is equal to the atmospheric pressure. Since adding a solute lowers the vapor pressure, we would expect a higher temperature to be required before boiling can begin. This phenomenon, known as boiling point elevation , occurs whenever a solute is dissolved into a pure solvent.
The mitotic spindle is an apparatus of microtubules that controls chromosome movement during what?	prometaphase	anaphase	metaphase	mitosis	null
Pluto’s orbit is in the kuiper?	zone	field	area	belt	Pluto’s orbit is in the Kuiper belt. We have discovered more than 200 million Kuiper belt objects. Pluto has 3 moons of its own. The largest, Charon, is big. Some scientists think that Pluto-Charon system is a double dwarf planet ( Figure below ). Two smaller moons, Nix and Hydra, were discovered in 2005.
What does fluoride in toothpaste help prevent?	plaque build up	cavities	gum disease	tooth decay	Figure 15.9 Fluoride, found in many toothpastes, helps prevent tooth decay (credit: Kerry Ceszyk). Unfortunately, excess fluoride can negate its advantages. Natural sources of drinking water in various parts of the world have varying concentrations of fluoride, and places where that concentration is high are prone to certain health risks when there is no other source of drinking water. The most serious side effect of excess fluoride is the bone disease, skeletal fluorosis. When excess fluoride is in the body, it can cause the joints to stiffen and the bones to thicken. It can severely impact mobility and can negatively affect the thyroid gland. Skeletal fluorosis is a condition that over 2.7 million people suffer from across the world. So while fluoride can protect our teeth from decay, the US Environmental Protection Agency sets a maximum level of 4 ppm (4 mg/ L) of fluoride in drinking water in the US. Fluoride levels in water are not regulated in all countries, so fluorosis is a problem in areas with high levels of fluoride in the groundwater.
The mass of 1 mol of molecules in grams is numerically equivalent to the mass of how many molecules in atomic mass units?	half	ten	two	one	The mole concept can be extended to masses of formula units and molecules as well. The mass of 1 mol of molecules (or formula units) in grams is numerically equivalent to the mass of one molecule (or formula unit) in atomic mass units. For example, a single molecule of O2 has a mass of 32.00 u, and 1 mol of O2 molecules has a mass of 32.00 g. As with atomic mass unit–based masses, to obtain the mass of 1 mol of a substance, we simply sum the masses of the individual atoms in the formula of that substance. The mass of 1 mol of a substance is referred to as its molar mass, whether the substance is an element, an ionic compound, or a covalent compound.
A diagram that represents feeding relationships is also called what?	form chain	life chart	fuel chain	food chain	Food chains and food webs are diagrams that represent feeding relationships. Essentially, they show who eats whom. In this way, they model how energy and matter move through ecosystems.
What is touching a charged object to the earth called?	insulating	drifting	stabilizing	grounding	Touching a charged object to the earth is called grounding.
Branchiopoda are mostly small, freshwater animals that feed on?	fishery and detritus	algae and plankton	nutrient and detritus	plankton and detritus	Branchiopoda Mostly small, freshwater animals that feed on plankton and detritus. Brine shrimp.
What is the name for groups of tens to hundreds of thousands of stars?	elliptical clusters	nebuli	constellations	globular clusters	Globular clusters ( Figure below ) are groups of tens to hundreds of thousands of stars. Gravity holds these stars tightly together. Globular clusters have a definite, spherical shape. They contain mostly old, reddish stars. Near the center of a globular cluster, the stars are closer together. The heart of the globular cluster M13 has hundreds of thousands of stars. M13 is 145 light years in diameter. The cluster contains red and blue giant stars.
Proteins may be defined as compounds of high molar mass consisting largely or entirely of chains of these?	enzymes	nucleic acids	fatty acids	amino acids	Proteins may be defined as compounds of high molar mass consisting largely or entirely of chains of amino acids. Their masses range from several thousand to several million daltons (Da). In addition to carbon, hydrogen, and oxygen atoms, all proteins contain nitrogen and sulfur atoms, and many also contain phosphorus atoms and traces of other elements. Proteins serve a variety of roles in living organisms and are often classified by these biological roles, which are summarized in Table 18.1 "Classification of Proteins by Biological Function". Muscle tissue is largely protein, as are skin and hair. Proteins are present in the blood, in the brain, and even in tooth enamel. Each type of cell in our bodies makes its own specialized proteins, as well as proteins common to all or most cells.
Continental drift and mantle convection are supported by data originating where?	the sun	ocean's surface	the moon	seafloor	Seafloor spreading is a mixture different ideas and data. Continental drift and mantle convection are supported by bathymetric and magnetic data from the seafloor.
Baroreceptors are specialized stretch receptors located within thin areas of blood vessels and heart chambers that respond to the degree of stretch caused by the presence of this?	bacteria	bile	water	blood	Baroreceptor Reflexes Baroreceptors are specialized stretch receptors located within thin areas of blood vessels and heart chambers that respond to the degree of stretch caused by the presence of blood. They send impulses to the cardiovascular center to regulate blood pressure. Vascular baroreceptors are found primarily in sinuses (small cavities) within the aorta and carotid arteries: The aortic sinuses are found in the walls of the ascending aorta just superior to the aortic valve, whereas the carotid sinuses are in the base of the internal carotid arteries. There are also low-pressure baroreceptors located in the walls of the venae cavae and right atrium. When blood pressure increases, the baroreceptors are stretched more tightly and initiate action potentials at a higher rate. At lower blood pressures, the degree of stretch is lower and the rate of firing is slower. When the cardiovascular center in the medulla oblongata receives this input, it triggers a reflex that maintains homeostasis (Figure 20.18): • When blood pressure rises too high, the baroreceptors fire at a higher rate and trigger parasympathetic stimulation of the heart. As a result, cardiac output falls. Sympathetic stimulation of the peripheral arterioles will also decrease, resulting in vasodilation. Combined, these activities cause blood pressure to fall. • When blood pressure drops too low, the rate of baroreceptor firing decreases. This will trigger an increase in sympathetic stimulation of the heart, causing cardiac output to increase. It will also trigger sympathetic stimulation of the peripheral vessels, resulting in vasoconstriction. Combined, these activities cause blood pressure to rise.
What structure forms a barrier between the cytoplasm and the environment outside the cell?	Flippases	Lipid bilayer	Cytoskeleton	cell membrane	The cell membrane is like the bag holding the Jell-O. It encloses the cytoplasm of the cell. It forms a barrier between the cytoplasm and the environment outside the cell. The function of the cell membrane is to protect and support the cell. It also controls what enters or leaves the cell. It allows only certain substances to pass through. It keeps other substances inside or outside the cell.
What are waxes made up of?	long - chain pyroclastic acids	long - project fatty acids	long-chain natural acids	long-chain fatty acids	Another category of lipid molecule is waxes. Waxes are esters of long-chain fatty acids and long-chain alcohols. Waxes are soft solids with generally low melting points and are insoluble in water. The Figure below shows the structure of cetyl palmitate, a natural wax present in sperm whales.

Science works hand in hand with what for the advancement of both?

banks

industry

government

technology

Although they have different goals, technology and science work hand in hand. Each helps the other advance. Scientific knowledge is needed to create new technologies. New technologies are used to further science. The microscope is a good example. Scientific knowledge of light allowed 17 th century lens makers to make the first microscopes. This new technology let scientists view a world of tiny objects they had never before seen. Figure below describes other examples.

Which part of the brain is responsible for working memory?

brain stem

amygdala

cerebellum

prefrontal cortex

14.3 Motor Responses The motor components of the somatic nervous system begin with the frontal lobe of the brain, where the prefrontal cortex is responsible for higher functions such as working memory. The integrative and associate functions of the prefrontal lobe feed into the secondary motor areas, which help plan movements. The premotor cortex and supplemental motor area then feed into the primary motor cortex that initiates movements. Large Betz cells project through the corticobulbar and corticospinal tracts to synapse on lower motor neurons in the brain stem and ventral horn of the spinal cord, respectively. These connections are responsible for generating movements of skeletal muscles. The extrapyramidal system includes projections from the brain stem and higher centers that influence movement, mostly to maintain balance and posture, as well as to maintain muscle tone. The superior colliculus and red nucleus in the midbrain, the vestibular nuclei in the medulla, and the reticular formation throughout the brain stem each have tracts projecting to the spinal cord in this system. Descending input from the secondary motor cortices, basal nuclei, and cerebellum connect to the origins of these tracts in the brain stem. All of these motor pathways project to the spinal cord to synapse with motor neurons in the ventral horn of the spinal cord. These lower motor neurons are the cells that connect to skeletal muscle and cause contractions. These neurons project through the spinal nerves to connect to the muscles at neuromuscular junctions. One motor neuron connects to multiple muscle fibers within a target muscle. The number of fibers that are innervated by a single motor neuron varies on the basis of the precision necessary for that muscle and the amount of force necessary for that motor unit. The quadriceps, for example, have many fibers controlled by single motor neurons for powerful contractions that do not need to be precise. The extraocular muscles have only a small number of fibers controlled by each motor neuron because moving the eyes does not require much force, but needs to be very precise. Reflexes are the simplest circuits within the somatic nervous system. A withdrawal reflex from a painful stimulus only requires the sensory fiber that enters the spinal cord and the motor neuron that projects to a muscle. Antagonist and postural muscles can be coordinated with the withdrawal, making the connections more complex. The simple, single neuronal.

What are bundles of collecting ducts that transport urine made by nephrons to the calyces of the kidney for excretion?

cuticle

cartoid

esophagus

papillae

Internal Anatomy A frontal section through the kidney reveals an outer region called the renal cortex and an inner region called the medulla (Figure 25.8). The renal columns are connective tissue extensions that radiate downward from the cortex through the medulla to separate the most characteristic features of the medulla, the renal pyramids and renal papillae. The papillae are bundles of collecting ducts that transport urine made by nephrons to the calyces of the kidney for excretion. The renal columns also serve to divide the kidney into 6–8 lobes and provide a supportive framework for vessels that enter and exit the cortex. The pyramids and renal columns taken together constitute the kidney lobes.

What do snakes use to smell things?

their nose

their mouth

their eyes

their tongue

Most reptiles have good eyesight and a keen sense of smell. Snakes smell scents in the air using their forked tongue (see Figure below ). This helps them locate prey. Some snakes have heat-sensing organs on their head that help them find endothermic prey, such as small mammals and birds.

Cardiac muscle normally has what kind of oxygen-using metabolism?

anarobic

digestive

glucose

aerobic

Cardiac Muscle Metabolism Normally, cardiac muscle metabolism is entirely aerobic. Oxygen from the lungs is brought to the heart, and every other organ, attached to the hemoglobin molecules within the erythrocytes. Heart cells also store appreciable amounts of oxygen in myoglobin. Normally, these two mechanisms, circulating oxygen and oxygen attached to myoglobin, can supply sufficient oxygen to the heart, even during peak performance. Fatty acids and glucose from the circulation are broken down within the mitochondria to release energy in the form of ATP. Both fatty acid droplets and glycogen are stored within the sarcoplasm and provide additional nutrient supply. (Seek additional content for more detail about metabolism.

Burning fossil fuels releases what into the atmosphere?

nitrogen dioxide

carbon monoxide

phosphorus dioxide

carbon dioxide

Burning organic material, such as fossil fuels, releases carbon dioxide.

Cnidarians are an ancient phylum of what?

arthropods

sporozoans

fungi

eumetazoans

33.2 Cnidarians are an ancient phylum of eumetazoans.

What theory states that both energy and matter have characteristics of waves under some conditions and characteristics of particles under other conditions?

atomic theory

static theory

big bang theory

quantum theory

Most definitions of quantum theory and quantum mechanics offer the same description for both. These definitions essentially describe quantum theory as a theory in which both energy and matter have characteristics of waves under some conditions and characteristics of particles under other conditions.

At which location is the earth hottest?

meridian

desert

seabed

equator

Earth is hottest at the Equator and gets cooler toward the poles. The differences in heating create huge convection currents in the troposphere. At the Equator, for example, warm air rises up to the tropopause. When it can’t rise any higher, it flows north or south.

What is process of producing eggs in the ovary called?

vaginalis

menstruation

morphogenesis

oogenesis

The process of producing eggs in the ovary is called oogenesis . Eggs, like sperm, are haploid cells, and their production occurs in several steps that involve different types of cells, as shown in Figure below . You can follow the process of oogenesis in the figure as you read about it below.

What protein is hair mostly made of?

Actin

coronin

Dystrophin

keratin

null

What is it called when the vesicle and target membrane fuse?

pathogen fusion

tendon fusion

enamel fusion

vesicle fusion

For a vesicle to release its contents to a cell organelle or to the outside of the cell, the vesicle and target membrane must fuse. This process is called vesicle fusion. Fusion between the vesicle and a target membrane occurs in one of two ways: full fusion or "kiss-and-run" fusion. In a full fusion process, the vesicle phospholipids fully incorporate into the plasma membrane. The vesicle can only be reformed and by a clathrin-coat-dependent process. With kiss-and-run fusion, the vesicle reforms after the release of its material. This allows the rapid release of materials from a synaptic vesicle. In this type of fusion, the vesicle forms a fusion pore or porosome in the presynaptic membrane and releases its neurotransmitters across the synapse, after which the vesicle reforms, allowing it to be reused.

What is the term for the number of covalent bonds an atom can form?

covalent number

atomic number

gradient

valence

null

Momentum can be expressed as the product of mass and what else?

acceleration

density

direction

velocity

If a bowling ball and a ping-pong ball are each moving with a velocity of 5 mph, you intuitively understand that it will require more effort to stop the bowling ball than the ping pong ball because of the greater mass of the bowling ball. Similarly, if you have two bowling balls, one moving at 5 mph and the other moving at 10 mph, you know it will take more effort to stop the ball with the greater speed. It is clear that both the mass and the velocity of a moving object contribute to what is necessary to change the motion of the moving object. The product of the mass and velocity of an object is called its momentum . Momentum is a vector quantity that has the same direction as the velocity of the object and is represented by a lowercase letter p .

A carbon atom with 6 protons and 8 neutrons is more specifically known as?

carbon 6

carbon 12

carbon 8

carbon 14

An example of a radioisotope is carbon-14. All carbon atoms have 6 protons, and most have 6 neutrons. These carbon atoms are called carbon-12, where 12 is the mass number (6 protons + 6 neutrons). A tiny percentage of carbon atoms have 8 neutrons instead of the usual 6. These atoms are called carbon-14 (6 protons + 8 neutrons). The nuclei of carbon-14 are unstable because they have too many neutrons. To be stable, a small nucleus like carbon, with just 6 protons, must have a 1:1 ratio of protons to neutrons. In other words, it must have the same number of neutrons as protons. In a large nucleus, with many protons, the ratio must be 2:1 or even 3:1 protons to neutrons.

Who was the first person known to use a telescope to study the sky?

Einstein

Copernicus

darwin

galileo

Galileo was the first person known to use a telescope to study the sky. His discoveries helped change the way humans think about the universe.

What kind of decay is electron capture a type of?

alpha decay

gamma decay

gradual decay

beta decay

since we use the masses of neutral atoms. Electron capture is the third type of beta decay. Here, a nucleus captures an inner-shell electron and undergoes a nuclear + reaction that has the same effect as β decay. Electron capture is sometimes denoted by the letters EC. We know that electrons cannot reside in the nucleus, but this is a nuclear reaction that consumes the electron and occurs spontaneously only when the products have less mass than the parent plus the electron. If a nuclide ZA X N is known to undergo electron capture, then its electron capture equation is A Z XN.

What is the result of a reaction between sulfur trioxide and water?

hydrochloric acid

nitric acid

acetic acid

sulfuric acid

Sulfur trioxide gas reacts with water to form sulfuric acid. This is an unfortunately common reaction that occurs in the atmosphere in some places where oxides of sulfur are present as pollutants. The acid formed in the reaction falls to the ground as acid rain.

Fragmentation with subsequent regeneration is a method of what, exhibited by animals such as sea stars?

microscopic reproduction

sexual reproduction

bacteria reproduction

asexual reproduction

Watch a video (http://openstaxcollege. org/l/budding_hydra) of a hydra budding. Fragmentation Fragmentation is the breaking of the body into two parts with subsequent regeneration. If the animal is capable of fragmentation, and the part is big enough, a separate individual will regrow. For example, in many sea stars, asexual reproduction is accomplished by fragmentation. Figure 43.4 illustrates a sea star for which an arm of the individual is broken off and regenerates a new sea star. Fisheries workers have been known to try to kill the sea stars eating their clam or oyster beds by cutting them in half and throwing them back into the ocean. Unfortunately for the workers, the two parts can each regenerate a new half, resulting in twice as many sea stars to prey upon the oysters and clams. Fragmentation also occurs in annelid worms, turbellarians, and poriferans.

What happens to atoms during a substitution reaction?

disintegrate

impaction

fusion

replace another in a molecule

A substitution reaction is a reaction in which one or more atoms replace another atom or group of atoms in a molecule. Alkyl halides are formed by the substitution of a halogen atom for a hydrogen atom. When methane reacts with chlorine gas, ultraviolet light can act as a catalyst for the reaction.

What lines the lungs and helps sweep mucus and pathogens out of the lungs?

villi

actin

alveoli

cilia

Charles Daghlian. Cilia lining the lungs help sweep mucus and pathogens out of the lungs . Public Domain.

Because most gas particles in the atmosphere are concentrated close to earth's surface, air pressure is greatest where?

atmosphere

ground level

seabed floor

at sea level

We live in a “sea” of air called the atmosphere. Can you feel the air in the atmosphere pressing against you? Not usually, but air actually exerts a lot of pressure because there’s so much of it. The atmosphere rises high above Earth’s surface, so it contains a huge number of gas particles. Most of them are concentrated close to Earth’s surface because of gravity and the weight of all the air in the atmosphere above them. As a result, air pressure is greatest at sea level and drops rapidly as you go higher in altitude. The Figure below shows how air pressure falls from sea level to the top of the atmosphere. In the graph, air pressure is measured in a unit called the millibar (mb). The SI unit of pressure is newton per square centimeter (N/cm 2 ).

Control rods containing nuclides that very strongly absorb neutrons are used to adjust what?

thermal flux

nuclei flux

fission flux

neutron flux

Control rods containing nuclides that very strongly absorb neutrons are used to adjust neutron flux. To produce large power, reactors contain hundreds to thousands of critical masses, and the chain reaction easily becomes self-sustaining, a condition called criticality. Neutron flux should be carefully regulated to avoid an exponential increase in fissions, a condition called supercriticality. Control rods help prevent overheating, perhaps even a meltdown or explosive disassembly. The water that is 235 used to thermalize neutrons, necessary to get them to induce fission in U , and achieve criticality, provides a negative.

All radioactive nuclides emit high-energy particles or what?

isotopes

magnetic fields

thermal energy

electromagnetic waves

The increased use of radioisotopes has led to increased concerns over the effects of these materials on biological systems (such as humans). All radioactive nuclides emit high-energy particles or electromagnetic waves. When this radiation encounters living cells, it can cause heating, break chemical bonds, or ionize molecules. The most serious biological damage results when these radioactive emissions fragment or ionize molecules. For example, alpha and beta particles emitted from nuclear decay reactions possess much higher energies than ordinary chemical bond energies. When these particles strike and penetrate matter, they produce ions and molecular fragments that are extremely reactive. The damage this does to biomolecules in living organisms can cause serious malfunctions in normal cell processes, taxing the organism’s repair mechanisms and possibly causing illness or even death (Figure 21.30).

What process is the synthesis of glucose from pyruvate, lactate and glycerol?

photosynthesis

hydrolysis

glycolysis

gluconeogenesis

Gluconeogenesis is the synthesis of glucose from pyruvate, lactate, glycerol,.

What is the creation of a new species called?

mutation

evolution

synthesis

speciation

The creation of a new species is called speciation . Most new species develop naturally. But humans have also artificially created new breeds and species for thousands of years.

What do humans use to make observations?

nutrients

hormones

blood

senses

Make observations. Observations refer to anything detected with one or more senses. The senses include sight, hearing, touch, smell, and taste.

The human penis contains the urethra, as well as how many cylinders of spongy erectile tissue?

five

Zero

nine

three

null

When water freezes, it expands in volume as what is formed?

energy

movement

plasma

ice

Ice is an interesting and useful material. It can be used to cool food and keep it fresh. It can provide recreation, such as ice-skating. Ice can do great damage when it freezes – roads can buckle, houses can be damaged, water pipes can burst. All this happens because of a unique property of water and ice. When water freezes, it expands in volume as ice is formed.

What is a substance or object that absorbs and dissipates heat but does not experience a corresponding increase in temperature?

heat dispeller

heat diffuser

heat storer

heat sink

Water as a Heat Sink A heat sink is a substance or object that absorbs and dissipates heat but does not experience a corresponding increase in temperature. In the body, water absorbs the heat generated by chemical reactions without greatly increasing in temperature. Moreover, when the environmental temperature soars, the water stored in the body helps keep the body cool. This cooling effect happens as warm blood from the body’s core flows to the blood vessels just under the skin and is transferred to the environment. At the same time, sweat glands release warm water in sweat. As the water evaporates into the air, it carries away heat, and then the cooler blood from the periphery circulates back to the body core.

Vesicles can be classified by their contents and what else?

color

example

smell

function

Vesicles can be classified by their contents and function.

The main function of this organ is to filter the blood and remove unwanted red blood cells?

heart

pancreas

kidney

spleen

Organs of the lymphatic system include the tonsils, thymus gland and spleen. The thymus gland produces T cells or T-lymphocytes (see below) and the spleen and tonsils help in fighting infections. The spleen’s main function is to filter the blood, removing unwanted red blood cells. The spleen also detects viruses and bacteria and triggers the release of pathogen fighting cells.

The brain case consists of eight bones which include the paired parietal and temporal bones, plus the unpaired frontal, occipital, sphenoid, and which other bone?

posterior

altoid

perpendicular

ethmoid

The brain case consists of eight bones. These include the paired parietal and temporal bones, plus the unpaired frontal, occipital, sphenoid, and ethmoid bones.

What can have complex effects on soil nutrient concentrations?

eukaryotes

the sun

sediments

prokaryotes

null

Rems, rads, and curies are all used to measure what?

thermal energy

gravity

potential energy

radioactivity

Radioactivity can be expressed in a variety of units, including rems, rads, and curies.

What governs motions of stars, galaxies and other celestial objects orbiting one another?

magnetic force

electrical force

frictional force

gravitational force

6.6 Satellites and Kepler’s Laws: An Argument for Simplicity Examples of gravitational orbits abound. Hundreds of artificial satellites orbit Earth together with thousands of pieces of debris. The Moon’s orbit about Earth has intrigued humans from time immemorial. The orbits of planets, asteroids, meteors, and comets about the Sun are no less interesting. If we look further, we see almost unimaginable numbers of stars, galaxies, and other celestial objects orbiting one another and interacting through gravity. All these motions are governed by gravitational force, and it is possible to describe them to various degrees of precision. Precise descriptions of complex systems must be made with large computers. However, we can describe an important class of orbits without the use of computers, and we shall find it instructive to study them. These orbits have the following characteristics: 1. A small mass.

The numbers and types of species living in what groups generally change through time, a process called ecological succession?

biospheres

movements

regions

communities

Communities are not usually static. The numbers and types of species that live in them generally change through time. This is called ecological succession . Important cases of succession are primary and secondary succession.

Claw hammers and pulleys are examples of simple machines that do what to the direction of force applied by the user?

nothing

neutralize it

maintain it

reverse it

Some machines change the direction of the force applied by the user. They may or may not also change the strength of the force or the distance over which it is applied. Two examples of machines that work in this way are claw hammers and the rope systems (pulleys) that raise or lower flags on flagpoles. Figure below explains how these machines work. In each case, the direction of the force applied by the user is reversed by the machine. How does this make it easier to do the job?.

A circular coral reef could indicate the earlier existence of what?

tsunami

landslide

avalanche

volcano

Reefs can form interesting shapes in the oceans. Remember that there are many volcanoes in the ocean. Coral reefs can form on volcanoes in tropical water. Since the volcanoes are cones, the reef forms in a circle around the volcano. Eventually the volcano becomes inactive. The mountain subsides and erodes so that it is below sea level. This leaves a circular coral reef ( Figure below ).

Many fungi protect themselves from parasites and predators by producing what?

pheromes

gaseous chemicals

ammonia

toxic chemicals

Many fungi protect themselves from parasites and predators by producing toxic chemicals. If people eat toxic fungi, they may experience digestive problems, hallucinations, organ failure, and even death. Most cases of mushroom poisoning are due to mistaken identity. That’s because many toxic mushrooms look very similar to safe, edible mushrooms. An example is shown in Figure below .

Acid rain falling in lakes can kill aquatic organisms by lowering what?

food level

color level

saliva level

ph level

If acid rain falls into lakes, it lowers the pH of the water and may kill aquatic organisms. If it falls on the ground, it may damage soil and soil organisms. If it falls on plants, it may make them sick or even kill them. Acid rain also damages stone buildings, bridges, and statues, like the one in Figure below .

What do plant and fungi cells have that animal cells lack?

cell swamps

cell holes

cell ridges

cell walls

null

Which type of energy holds atoms together?

curve energy

atomic energy

nuclear energy

bond energy

Atoms are held together by a certain amount of energy called bond energy.

What type of energy is the energy stored in an object due to its position?

directional energy

spontaneous energy

mechanical energy

potential energy

Potential energy is the energy stored in an object due to its position. A bouncing ball at the top of a bounce, just before it starts to fall, has potential energy. For that instant, the ball is not moving, but it has the potential to move because gravity is pulling on it. Once the ball starts to fall, the potential energy changes to kinetic energy. When the ball hits the ground, it gains potential energy from the impact. The potential energy changes to kinetic energy when the ball bounces back up into the air. As the ball gains height, it regains potential energy because of gravity.

What is the amount of product that may be produced by a reaction under specified conditions called?

reactant

solute

catalytic yield

theoretical yield

Percent Yield The amount of product that may be produced by a reaction under specified conditions, as calculated per the stoichiometry of an appropriate balanced chemical equation, is called the theoretical yield of the reaction. In practice, the amount of product obtained is called the actual yield, and it is often less than the theoretical yield for a number of reasons. Some reactions are inherently inefficient, being accompanied by side reactions that generate other products. Others are, by nature, incomplete (consider the partial reactions of weak acids and bases discussed earlier in this chapter). Some products are difficult to collect without some loss, and so less than perfect recovery will reduce the actual yield. The extent to which a reaction’s theoretical yield is achieved is commonly expressed as its percent yield: percent yield =.

Sometimes referred to as air, what do we call the mixture of gases that surrounds the planet?

hemisphere

outer space

galaxy

atmosphere

Why is Earth the only planet in the solar system known to have life? The main reason is Earth’s atmosphere. The atmosphere is a mixture of gases that surrounds the planet. We also call it air. The gases in the air include nitrogen, oxygen, and carbon dioxide. Along with water vapor, air allows life to survive. Without it, Earth would be a harsh, barren world.

What is another term for seed plants?

petals

stems

sporozoans

spermatophytes

Most vascular plants are seed plants, or spermatophytes. They reproduce with seeds and pollen.

Kinetic theory is the atomistic description of what as well as liquids and solids?

fluids

plasmas

molecules

gases

13.4 Kinetic Theory: Atomic and Molecular Explanation of Pressure and Temperature • Kinetic theory is the atomistic description of gases as well as liquids and solids. • Kinetic theory models the properties of matter in terms of continuous random motion of atoms and molecules. • The ideal gas law can also be expressed as.

Though it can change states, and it often does, what cannot be created or destroyed?

volums

mass

water content

matter

Then, the muscles of the uterus start contracting. The contractions get stronger and closer together. They may go on for hours. Eventually, the contractions squeeze the baby out of the uterus. Once the baby enters the vagina, the mother starts pushing. She soon pushes the baby through the vagina and out of her body.

What are the long carbon chains that make up lipids?

nucleic acids

proteins

carbohydrates

fatty acids

Lipids are made up of long carbon chains called fatty acids. Like hydrocarbons, fatty acids may be saturated or unsaturated. Figure below shows structural formulas for two small fatty acids. One is saturated and one is unsaturated.

As the anterior end of the neural tube starts to develop into the brain, it undergoes a couple of enlargements; the result is the production of these?

tributaries - like vesicles

cyclinder-like vesicles

square-like vesicles

sac-like vesicles

Primary Vesicles As the anterior end of the neural tube starts to develop into the brain, it undergoes a couple of enlargements; the result is the production of sac-like vesicles. Similar to a child’s balloon animal, the long, straight neural tube begins to take on a new shape. Three vesicles form at the first stage, which are called primary vesicles. These vesicles are given names that are based on Greek words, the main root word being enkephalon, which means “brain” (en- = “inside”; kephalon = “head”). The prefix to each generally corresponds to its position along the length of the developing nervous system. The prosencephalon (pros- = “in front”) is the forward-most vesicle, and the term can be loosely translated to mean forebrain. The mesencephalon (mes- = “middle”) is the next vesicle, which can be called the midbrain. The third vesicle at this stage is the rhombencephalon. The first part of this word is also the root of the word rhombus, which is a geometrical figure with four sides of equal length (a square is a rhombus with 90° angles). Whereas prosencephalon and mesencephalon translate into the English words forebrain and midbrain, there is not a word for “four-sided-figure-brain. ” However, the third vesicle can be called the hindbrain. One way of thinking about how the brain is arranged is to use these three regions—forebrain, midbrain, and hindbrain—which are based on the primary vesicle stage of development (Figure 13.3a).

What makes the sun glow brightly?

sun bursts

radiation

ultraviolet rays

nuclear fusion

What causes the sun to glow so brightly? The answer is nuclear fusion. Nuclear fusion is a type of nuclear reaction, and it releases a huge amount of energy.

Lens faces can generally either be concave, or what, which is the opposite of concave?

spherical

hollow

elliptical

convex

One or both of the lens faces is part of a sphere and can be concave or convex.

Part of the fossil record, stromatolites belong to what rock group and are formed when minerals are precipitated out of water by prokaryotes in a microbial mat?

crystalline

metamorphic

igneous

sedimentary

Stromatolites Fossilized microbial mats represent the earliest record of life on Earth. A stromatolite is a sedimentary structure formed when minerals are precipitated out of water by prokaryotes in a microbial mat (Figure 22.3). Stromatolites form layered rocks made of carbonate or silicate. Although most stromatolites are artifacts from the past, there are places on Earth where stromatolites are still forming. For example, growing stromatolites have been found in the Anza-Borrego Desert State Park in San Diego County, California.

Vinegar is an example of what type of acid?

carbonic

ascorbic

acetic

carboxylic

Carboxylic acid is a carbonyl in which in which the carbon atom is bonded to an OH group on one side and either a carbon or hydrogen atom on the other. Carboxylic acids are weak acids, for example, vinegar.

What system of the body is most involved in the immune response?

anomalous system

primordial system

circulatory system

lymphatic system

The immune response mainly involves the lymphatic system. The lymphatic system is a major part of the immune system. It produces leukocytes called lymphocytes. Lymphocytes are the key cells involved in the immune response. They recognize and help destroy particular pathogens in body fluids and cells. They also destroy certain cancer cells.

The highest level of organization in ecology is known as what?

reserves

topmast

preserves

biosphere

The biosphere consists of all the parts of Earth where life can be found. This is the highest level of organization in ecology. It includes all of the other levels below it. The biosphere consists of all the world’s biomes, both terrestrial and aquatic.

Food allergies, ulcers, and heartburn are diseases of what system of the body?

skeletal system

nervous system

circulatory system

digestive system

Digestive system diseases include food allergies, ulcers, and heartburn.

Bases turn red litmus paper which color?

white

pink

white

blue

Indicator compounds such as litmus can be used to detect bases. Bases turn red litmus paper blue.

What two elements do ribosome consist of?

malassezia and proteins

lafleur and proteins

dna

rrna and proteins

The ribosome consists of rRNA and proteins. It reads the sequence of codons in mRNA.

What is the term for the flow of charge that a voltage source creates?

velocity

force

output

current

measured at various points in a circuit, it will be seen to increase at the voltage source and decrease at the resistor. Voltage is similar to fluid pressure. The voltage source is like a pump, creating a pressure difference, causing current—the flow of charge. The resistor is like a pipe that reduces pressure and limits flow because of its resistance. Conservation of energy has important consequences here. The voltage source supplies energy (causing an electric field and a current), and the resistor converts it to another form (such as thermal energy). In a simple circuit (one with a single simple resistor), the voltage supplied by the source equals the voltage drop across the resistor, since PE = qΔV , and the same q flows through each. Thus the energy supplied by the voltage source and the energy converted by the resistor are equal. (See Figure 20.9.

What happens to a cell's efficiency as it grows in size?

multiplies

increases

splits in half

decreases

Small size, in general, is necessary for all cells, whether prokaryotic or eukaryotic. Let’s examine why that is so. First, we’ll consider the area and volume of a typical cell. Not all cells are spherical in shape, but most tend to approximate a sphere. You may remember from your high school geometry course that the formula for the surface area of a sphere is 4πr2, while the formula for its volume is 4πr3/3. Thus, as the radius of a cell increases, its surface area increases as the square of its radius, but its volume increases as the cube of its radius (much more rapidly). Therefore, as a cell increases in size, its surface area-to-volume ratio decreases. This same principle would apply if the cell had the shape of a cube (Figure 4.7). If the cell grows too large, the plasma membrane will not have sufficient surface area to support the rate of diffusion required for the increased volume. In other words, as a cell grows, it becomes less efficient. One way to become more efficient is to divide; another way is to develop organelles that perform specific tasks. These adaptations lead to the development of more sophisticated cells called eukaryotic cells.

What is responsible not only for cell shape changes but also for cell migration?

cellulose

Golgi Apparatus

cytoplasm

cytoskeleton

null

What is performed to identify disease-causing genes?

ultrasound

bioremediation

inoculation

genetic testing

CHAPTER SUMMARY 17.1 Biotechnology Nucleic acids can be isolated from cells for the purposes of further analysis by breaking open the cells and enzymatically destroying all other major macromolecules. Fragmented or whole chromosomes can be separated on the basis of size by gel electrophoresis. Short stretches of DNA or RNA can be amplified by PCR. Southern and northern blotting can be used to detect the presence of specific short sequences in a DNA or RNA sample. The term “cloning” may refer to cloning small DNA fragments (molecular cloning), cloning cell populations (cellular cloning), or cloning entire organisms (reproductive cloning). Genetic testing is performed to identify disease-causing genes, and gene therapy is used to cure an inheritable disease. Transgenic organisms possess DNA from a different species, usually generated by molecular cloning techniques. Vaccines, antibiotics, and hormones are examples of products obtained by recombinant DNA technology. Transgenic plants are usually created to improve characteristics of crop plants.

What type of fossils are useful for determining the ages of rock layers?

trace fossils

cast fossils

mold fossils

index fossils

Fossils are the best form of evidence about the history of life on Earth. Fossils also give us clues about major geological events and past climates. Index fossils are useful for determining the ages of rock layers.

What type of organisms carry out their life processes through division of labor and have specialized cells that do specific job?

CompoundCellular

dermal

biomolecular

multicellular

Multicellular organisms carry out their life processes through division of labor. They have specialized cells that do specific jobs.

What defines the behavior of a compound?

location of atoms

size of atoms

area of atoms

group of atoms

In a compound, a group of atoms that define the behavior of the compound.

What collect sunlight on the roof of a house for energy?

asphalt shingles

infrared panels

clay tiles

solar panels

Solar panels collect sunlight on the roof of this house. The energy can be used to run the household.

The light reactions are the steps of photosynthesis that convert solar energy to what other type of energy?

radiation energy

kinetic energy

carbon energy

chemical energy

null

Water waves act as a mix of longitudinal and what other kind of wave?

variable wave

lateral wave

latitudinal

transverse wave

Water waves act as a mix of longitudinal and transverse waves. A typical water molecule pretty much moves in a circle when a wave passes through it.

What is the name for a fertilized cell that results from the uniting of two gametes?

sperm

chromosomes

eggs

zygote

Sexual reproduction involves two parents. As you can see from Figure below , in sexual reproduction, parents produce reproductive cells—called gametes —that unite to form an offspring. Gametes are haploid cells. This means they contain only half the number of chromosomes found in other cells of the organism. Gametes are produced by a type of cell division called meiosis , which is described in detail in a subsequent concept. The process in which two gametes unite is called fertilization . The fertilized cell that results is referred to as a zygote . A zygote is diploid cell, which means that it has twice the number of chromosomes as a gamete.

Caffeine and alcohol are two examples of what type of drug?

psilopsybin

nicotine

barbiturate

psychoactive

Drugs are chemicals that affect the body’s structure or function. Psychoactive drugs, such as caffeine and alcohol, affect the central nervous system by influencing the transmission of nerve impulses in the brain. Psychoactive drugs may be abused and lead to drug addiction.

By maintaining a relatively constant internal environment even when the external environment changes significantly, an animal achieves what?

eternal youth

hibernation

consciousness

homeostasis

null

What is the sticky, moist substance that covers mucous membranes called?

pus

saliva

phlegm

mucus

One defense of mucous membranes is the mucus they release. Mucus is a sticky, moist substance that covers mucous membranes. Most pathogens get stuck in the mucus before they can do harm to the body. Many mucous membranes also have cilia. Cilia in the lungs are pictured below ( Figure below ). Cilia are tiny finger-like projections. They move in waves and sweep mucus and trapped pathogens toward body openings. When you clear your throat or blow your nose, you remove mucus and pathogens from your body.

Most receptors in the dermis are encapsulated by what?

pathogenic tissue

tendons

bone tissue

connective tissue

null

The length of the route between two points is known as what?

shape

velocity

direction

distance

Distance is the length of the route between two points.

How did seismologists originally measure the intensity of an earthquake?

regolith scale

richter scale

Maxwell scale

mercalli scale

The ways seismologists measure an earthquake have changed over the decades. Initially, they could only measure what people felt and saw: the intensity. For this, they used the Mercalli scale.

What is the term for the distance that sound waves travel in a given amount of time?

sonic speed

velocity of sound

sound barrier

speed of sound

The speed of sound is the distance that sound waves travel in a given amount of time. You’ll often see the speed of sound given as 343 meters per second. But that’s just the speed of sound under a certain set of conditions, specifically, through dry air at 20 °C. The speed of sound may be very different through other matter or at other temperatures.

How much of its alleles does a plant pass on when it reproduces sexually?

all

a quarter

none

half

null

Using less energy or using energy more efficiently are the basic methods of what?

pressure conservation

demand conservation

moral conservation

energy conservation

There are two basic ways to conserve energy. You can use less energy. You can also use energy more efficiently.

What will a fertilized ovule develop into?

a gonad

a spore

a spermazoa

a seed

null

What type of particles do acids release, by definition?

fission ions

quarks

nucleic acids

hydrogen ions

Acids are molecular compounds that release hydrogen ions.

An alpha particle, which is relatively large and easily stopped by matter, is a type of what?

free emission

waste emission

plant emission

radioactive emission

Alpha, beta, and gamma emissions have different abilities to penetrate matter. The relatively large alpha particle is easily stopped by matter (although it may impart a significant amount of energy to the matter it contacts). Beta particles penetrate slightly into matter, perhaps a few centimeters at most. Gamma rays can penetrate deeply into matter and can impart a large amount of energy into the surrounding matter. Table 11.1 "The Three Main Forms of Radioactive Emissions" summarizes the properties of the three main types of radioactive emissions. Table 11.1 The Three Main Forms of Radioactive Emissions.

What does antifreeze do to the boiling point of coolant?

has no effect

lowers it

accelerates it

raises it

Flickr: EvelynGiggles, modified by CK-12 Foundation. Antifreeze raises the boiling point of coolant . CC BY 2.0.

What are rhythmic, involuntary contractions of the reproductive structures?

seizure

reproductive spasms

sexual paroxysms

orgasm

null

What happens when oppositely charged regions of neighboring water molecules are attracted to each other?

oxygen is released

potassium bonds form

metabolic bonds form

hydrogen bonds form

null

What occurs when the vapor pressure of a liquid is equal to the atmospheric pressure?

evaporation

freezing

melting

boiling

Recall that boiling occurs when the vapor pressure of a liquid is equal to the atmospheric pressure. Since adding a solute lowers the vapor pressure, we would expect a higher temperature to be required before boiling can begin. This phenomenon, known as boiling point elevation , occurs whenever a solute is dissolved into a pure solvent.

The mitotic spindle is an apparatus of microtubules that controls chromosome movement during what?

prometaphase

anaphase

metaphase

mitosis

null

Pluto’s orbit is in the kuiper?

zone

field

area

belt

Pluto’s orbit is in the Kuiper belt. We have discovered more than 200 million Kuiper belt objects. Pluto has 3 moons of its own. The largest, Charon, is big. Some scientists think that Pluto-Charon system is a double dwarf planet ( Figure below ). Two smaller moons, Nix and Hydra, were discovered in 2005.

What does fluoride in toothpaste help prevent?

plaque build up

cavities

gum disease

tooth decay

Figure 15.9 Fluoride, found in many toothpastes, helps prevent tooth decay (credit: Kerry Ceszyk). Unfortunately, excess fluoride can negate its advantages. Natural sources of drinking water in various parts of the world have varying concentrations of fluoride, and places where that concentration is high are prone to certain health risks when there is no other source of drinking water. The most serious side effect of excess fluoride is the bone disease, skeletal fluorosis. When excess fluoride is in the body, it can cause the joints to stiffen and the bones to thicken. It can severely impact mobility and can negatively affect the thyroid gland. Skeletal fluorosis is a condition that over 2.7 million people suffer from across the world. So while fluoride can protect our teeth from decay, the US Environmental Protection Agency sets a maximum level of 4 ppm (4 mg/ L) of fluoride in drinking water in the US. Fluoride levels in water are not regulated in all countries, so fluorosis is a problem in areas with high levels of fluoride in the groundwater.

The mass of 1 mol of molecules in grams is numerically equivalent to the mass of how many molecules in atomic mass units?

half

ten

two

one

The mole concept can be extended to masses of formula units and molecules as well. The mass of 1 mol of molecules (or formula units) in grams is numerically equivalent to the mass of one molecule (or formula unit) in atomic mass units. For example, a single molecule of O2 has a mass of 32.00 u, and 1 mol of O2 molecules has a mass of 32.00 g. As with atomic mass unit–based masses, to obtain the mass of 1 mol of a substance, we simply sum the masses of the individual atoms in the formula of that substance. The mass of 1 mol of a substance is referred to as its molar mass, whether the substance is an element, an ionic compound, or a covalent compound.

A diagram that represents feeding relationships is also called what?

form chain

life chart

fuel chain

food chain

Food chains and food webs are diagrams that represent feeding relationships. Essentially, they show who eats whom. In this way, they model how energy and matter move through ecosystems.

What is touching a charged object to the earth called?

insulating

drifting

stabilizing

grounding

Touching a charged object to the earth is called grounding.

Branchiopoda are mostly small, freshwater animals that feed on?

fishery and detritus

algae and plankton

nutrient and detritus

plankton and detritus

Branchiopoda Mostly small, freshwater animals that feed on plankton and detritus. Brine shrimp.

What is the name for groups of tens to hundreds of thousands of stars?

elliptical clusters

nebuli

constellations

globular clusters

Globular clusters ( Figure below ) are groups of tens to hundreds of thousands of stars. Gravity holds these stars tightly together. Globular clusters have a definite, spherical shape. They contain mostly old, reddish stars. Near the center of a globular cluster, the stars are closer together. The heart of the globular cluster M13 has hundreds of thousands of stars. M13 is 145 light years in diameter. The cluster contains red and blue giant stars.

Proteins may be defined as compounds of high molar mass consisting largely or entirely of chains of these?

enzymes

nucleic acids

fatty acids

amino acids

Proteins may be defined as compounds of high molar mass consisting largely or entirely of chains of amino acids. Their masses range from several thousand to several million daltons (Da). In addition to carbon, hydrogen, and oxygen atoms, all proteins contain nitrogen and sulfur atoms, and many also contain phosphorus atoms and traces of other elements. Proteins serve a variety of roles in living organisms and are often classified by these biological roles, which are summarized in Table 18.1 "Classification of Proteins by Biological Function". Muscle tissue is largely protein, as are skin and hair. Proteins are present in the blood, in the brain, and even in tooth enamel. Each type of cell in our bodies makes its own specialized proteins, as well as proteins common to all or most cells.

Continental drift and mantle convection are supported by data originating where?

the sun

ocean's surface

the moon

seafloor

Seafloor spreading is a mixture different ideas and data. Continental drift and mantle convection are supported by bathymetric and magnetic data from the seafloor.

Baroreceptors are specialized stretch receptors located within thin areas of blood vessels and heart chambers that respond to the degree of stretch caused by the presence of this?

bacteria

bile

water

blood

Baroreceptor Reflexes Baroreceptors are specialized stretch receptors located within thin areas of blood vessels and heart chambers that respond to the degree of stretch caused by the presence of blood. They send impulses to the cardiovascular center to regulate blood pressure. Vascular baroreceptors are found primarily in sinuses (small cavities) within the aorta and carotid arteries: The aortic sinuses are found in the walls of the ascending aorta just superior to the aortic valve, whereas the carotid sinuses are in the base of the internal carotid arteries. There are also low-pressure baroreceptors located in the walls of the venae cavae and right atrium. When blood pressure increases, the baroreceptors are stretched more tightly and initiate action potentials at a higher rate. At lower blood pressures, the degree of stretch is lower and the rate of firing is slower. When the cardiovascular center in the medulla oblongata receives this input, it triggers a reflex that maintains homeostasis (Figure 20.18): • When blood pressure rises too high, the baroreceptors fire at a higher rate and trigger parasympathetic stimulation of the heart. As a result, cardiac output falls. Sympathetic stimulation of the peripheral arterioles will also decrease, resulting in vasodilation. Combined, these activities cause blood pressure to fall. • When blood pressure drops too low, the rate of baroreceptor firing decreases. This will trigger an increase in sympathetic stimulation of the heart, causing cardiac output to increase. It will also trigger sympathetic stimulation of the peripheral vessels, resulting in vasoconstriction. Combined, these activities cause blood pressure to rise.

What structure forms a barrier between the cytoplasm and the environment outside the cell?

Flippases

Lipid bilayer

Cytoskeleton

cell membrane

The cell membrane is like the bag holding the Jell-O. It encloses the cytoplasm of the cell. It forms a barrier between the cytoplasm and the environment outside the cell. The function of the cell membrane is to protect and support the cell. It also controls what enters or leaves the cell. It allows only certain substances to pass through. It keeps other substances inside or outside the cell.

What are waxes made up of?

long - chain pyroclastic acids

long - project fatty acids

long-chain natural acids

long-chain fatty acids

Another category of lipid molecule is waxes. Waxes are esters of long-chain fatty acids and long-chain alcohols. Waxes are soft solids with generally low melting points and are insoluble in water. The Figure below shows the structure of cetyl palmitate, a natural wax present in sperm whales.