NilsML/retriever_dataset · Datasets at Hugging Face

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What series of reactions is common to fermentation and cellular respiration?	photosynthesis	spermatogenesis	metabolism	glycolysis	null
In which ways may sponges reproduce?	meiosis and mitosis	sexually and vertically	internally and externally	sexually and asexually	The sponge life cycle includes sexual reproduction. Sponges may also reproduce asexually.
What do barnacles anchor to?	scales	eggs	fossils	rocks	Mo Riza. Barnacles are adapted to the intertidal zone by anchoring to rocks . CC BY 2.0.
Organic compounds produced by what process provide the energy and building material for ecosystems?	glycolysis	cyclogenesis	nuclear fusion	photosynthesis	null
As you increase the temperature of a liquid what happens to the solubility of a solute?	viscosity increases	turbidity increases	hydrophilic increases	solubility increases	Temperature affects the solubility of a solute. However, it affects the solubility of gases differently than the solubility of solids and liquids.
The relative sizes of the atoms show several trends with regard to what visual method of organization?	oscillations table	vibrations table	chemistry table	periodic table	The relative sizes of the atoms show several trends with regard to the structure of the periodic table. Atoms become larger going down a column and smaller going across a period.
Toward the end of pregnancy, the synthesis of oxytocin receptors in what reproductive organ increases?	lungs	stomach	liver	uterus	Oxytocin When fetal development is complete, the peptide-derived hormone oxytocin (tocia- = “childbirth”) stimulates uterine contractions and dilation of the cervix. Throughout most of pregnancy, oxytocin hormone receptors are not expressed at high levels in the uterus. Toward the end of pregnancy, the synthesis of oxytocin receptors in the uterus increases, and the smooth.
If an animal eats large pieces of food it is known as a?	bulk producer	large consumer	many feeder	bulk feeder	null
What are the two vibrating fields that electromagnetic waves consist of?	radioactive and magnetic	flammable and magnetic	magnetic and mechanical	electric and magnetic	Electromagnetic waves are waves that consist of vibrating electric and magnetic fields. They transfer energy through matter or across space. The transfer of energy by electromagnetic waves is called electromagnetic radiation.
What is the process by which plants and animals increase in size?	activity	birth	reproduction	growth	null
How do endocrine hormones travel throughout the body?	in the lymph	in urea	in mucus	in the blood	Endocrine hormones travel throughout the body in the blood. However, each endocrine hormone affects only certain cells, called target cells.
The post-anal tail is at the end of the organism opposite what?	fingers	legs	knees	head	The post-anal tail is at the end of the organism opposite the head. It extends beyond the anus.
What is the term for the moles of solute divided by the kilograms of solvent?	kilocalorie	molar solvency	molar weight	molality	A final way to express the concentration of a solution is by its molality. The molality ( m ) of a solution is the moles of solute divided by the kilograms of solvent. A solution that contains 1.0 mol of NaCl dissolved into 1.0 kg of water is a “one-molal” solution of sodium chloride. The symbol for molality is a lower-case m written in italics.
Active transport moves substances from an area of lower concentration to an area of?	the same concentration	flat concentration	low concentration	higher concentration	Active transport requires energy because it moves substances from an area of lower to higher concentration. An example is the sodium-potassium pump. Another form of active transport is vesicle transport, which is needed for very large molecules.
How does the skin eliminates excess water and salts?	burn	peel	itch	sweat	The skin eliminates excess water and salts in sweat.
Organophosphates typically interfere with nerve signal transmission by inhibiting the enzymes that degrade what?	protein molecules	prototype molecules	potassium molecules	transmitter molecules	null
What is the horizontal distance between two waves, measured at a common point (crest to crest or trough to trough), called?	frequency	linear	absorption	wavelength	Seismic waves are just one type of wave. Sound and light also travel in waves. Every wave has a high point called a crest and a low point called a trough . The height of a wave from the center line to its crest is its amplitude . The horizontal distance between waves from crest to crest (or trough to trough) is its wavelength ( Figure below ).
Steroid hormones, such as cortisol and ecdysteroid, are lipids that contain four fused what?	oxide rings	acid rings	nitrogen rings	carbon rings	null
The solubility of gases, liquids, and solids are affected by changes in what?	volume	elevation	friction	temperature	The solubility of gases, liquids, and solids are affected by changes in temperature.
Only animals have muscle tissue and what other type of tissue?	cartilage	nonvascular tissue	vascular tissue	nervous	23.29 Characteristics of an Animal • There is no one universally accepted definition of an animal. The following treatment follows your text, beginning on page 876. • Animals: • Are multicellular, heterotrophic eukaryotes . • Lack the distinctive cell walls of plants & fungi • Share unique characteristics . • Share certain reproductive characteristics . • Other commonly used definitions . Animals are multicellular heterotrophic eukaryotes • Unfortunately, none of these traits is exclusive to animals: • Plants, fungi, and some algae are multicellular. • Many bacteria, protists, and all fungi are heterotrophic. • Everything other than bacteria and archaea are eukaryotic. • Moreover, all three of these characteristics also apply to fungi. • However, there is a difference here between animals and fungi. Animals generally take in their food through ingestion, or eating and swallowing something. Fungi are absorptive heterotrophs; they secrete their digestive enzymes onto their food, and then absorb the resulting nutrients. Animals share unique characteristics • Only animals have muscle tissue and nervous tissue. • Only animals have collagen, a structural protein • Only animals have the following types of intercellular junctions: (See pages 135 - 139, Figure 7.15 in your text for more information on these junctions.
What type of matter transmits light but scatters the light as it passes through?	a mirror	opaque matter	refractive matter	translucent matter	Translucent matter is matter that transmits light but scatters the light as it passes through. Light passes through translucent objects but you cannot see clearly through them because the light is scattered in all directions. The frosted glass panes at the bottom of the window above are translucent.
During an earthquake, the ground shakes as stored up energy is released from what?	grass	fossils	the soil	rocks	During an earthquake, the ground shakes as stored up energy is released from rocks.
Tunnel vision involves the loss of what visual fields?	underwater	distant	quickly-moving	peripheral	A unique clinical presentation that relates to this anatomic arrangement is the loss of lateral peripheral vision, known as bilateral hemianopia. This is different from “tunnel vision” because the superior and inferior peripheral fields are not lost. Visual field deficits can be disturbing for a patient, but in this case, the cause is not within the visual system itself. A growth of the pituitary gland presses against the optic chiasm and interferes with signal transmission. However, the axons projecting to the same side of the brain are unaffected. Therefore, the patient loses the outermost areas of their field of vision and cannot see objects to their right and left. Extending from the optic chiasm, the axons of the visual system are referred to as the optic tract instead of the optic nerve. The optic tract has three major targets, two in the diencephalon and one in the midbrain. The connection between the eyes and diencephalon is demonstrated during development, in which the neural tissue of the retina differentiates from that of the diencephalon by the growth of the secondary vesicles. The connections of the retina into the CNS are a holdover from this developmental association. The majority of the connections of the optic tract are to the thalamus—specifically, the lateral geniculate nucleus. Axons from this nucleus then project to the visual cortex of the cerebrum, located in the occipital lobe. Another target of the optic tract is the superior colliculus. In addition, a very small number of RGC axons project from the optic chiasm to the suprachiasmatic nucleus of the hypothalamus. These RGCs are photosensitive, in that they respond to the presence or absence of light. Unlike the photoreceptors, however, these photosensitive RGCs cannot be used to perceive images. By simply responding to the absence or presence of light, these RGCs can send information about day length. The perceived proportion of sunlight to darkness establishes the circadian rhythm of our bodies, allowing certain physiological events to occur at approximately the same time every day.
Systemic mycoses spread to internal organs, most commonly entering the body through this?	infestation system	digestive system	skeletal system	respiratory system	Systemic mycoses spread to internal organs, most commonly entering the body through the respiratory system. For example, coccidioidomycosis (valley fever) is commonly found in the southwestern United States, where the fungus resides in the dust. Once inhaled, the spores develop in the lungs and cause symptoms similar to those of tuberculosis. Histoplasmosis is caused by the dimorphic fungus Histoplasma capsulatum. It also causes pulmonary infections, and in rarer cases, swelling of the membranes of the brain and spinal cord. Treatment of these and many other fungal diseases requires the use of antifungal medications that have serious side effects. Opportunistic mycoses are fungal infections that are either common in all environments, or part of the normal biota. They mainly affect individuals who have a compromised immune system. Patients in the late stages of AIDS suffer from opportunistic mycoses that can be life threatening. The yeast Candida sp. , a common member of the natural biota, can grow unchecked and infect the vagina or mouth (oral thrush) if the pH of the surrounding environment, the person’s immune defenses, or the normal population of bacteria are altered. Mycetismus can occur when poisonous mushrooms are eaten. It causes a number of human fatalities during mushroompicking season. Many edible fruiting bodies of fungi resemble highly poisonous relatives, and amateur mushroom hunters are cautioned to carefully inspect their harvest and avoid eating mushrooms of doubtful origin. The adage “there are bold mushroom pickers and old mushroom pickers, but are there no old, bold mushroom pickers” is unfortunately true.
The three features that are unique to the large intestine are the teniae coli, haustra, and what?	binary appendages	radial appendages	disc appendages	epiploic appendages	Anatomy Three features are unique to the large intestine: teniae coli, haustra, and epiploic appendages (Figure 23.23). The teniae coli are three bands of smooth muscle that make up the longitudinal muscle layer of the muscularis of the large intestine, except at its terminal end. Tonic contractions of the teniae coli bunch up the colon into a succession of pouches called haustra (singular = hostrum), which are responsible for the wrinkled appearance of the colon. Attached to the teniae coli are small, fat-filled sacs of visceral peritoneum called epiploic appendages. The purpose of these is unknown. Although the rectum and anal canal have neither teniae coli nor haustra, they do have well-developed layers of muscularis that create the strong contractions needed for defecation.
Most living things build proteins from the same 20 different what?	acid peptides	uncommon acids	atomic isolates	amino acids	if the salt produced is an acidic salt.
What reaction, along with photosynthesis, provides energy to the vast majority of living things?	Internal Respiration	devices respiration	primarily respiration	cellular respiration	The chemical reactions of photosynthesis and cellular respiration together provide energy to virtually all living things on Earth.
Some animals increase body fat in winter to stay?	cold	thin	aware	warm	null
Coal, oil, and natural gas are examples of what, which forms when organic matter is under pressure for millions of years?	nuclear fission	complex carbohydrates	solar fuels	fossil fuels	Millions of years ago, there were so many dead plants and animals that they could not completely decompose before they were buried. They were covered over by soil or sand, tar or ice. These dead plants and animals are organic matter made out of cells full of carbon-containing organic compounds (carbohydrates, lipids, proteins and nucleic acids). What happened to all this carbon? When organic matter is under pressure for millions of years, it forms fossil fuels. Fossil fuels are coal, oil, and natural gas.
Protists play critically important ecological roles as producers and, on the other end of food webs, as what?	probiotics	dissolvers	absorbers	decomposers	Beneficial Protists Protists play critically important ecological roles as producers particularly in the world’s oceans. They are equally important on the other end of food webs as decomposers. Protists as Food Sources Protists are essential sources of nutrition for many other organisms. In some cases, as in plankton, protists are consumed directly. Alternatively, photosynthetic protists serve as producers of nutrition for other organisms by carbon fixation. For instance, photosynthetic dinoflagellates called zooxanthellae pass on most of their energy to the coral polyps that house them (Figure 13.19). In this mutually beneficial relationship, the polyps provide a protective environment and nutrients for the zooxanthellae. The polyps secrete the calcium carbonate that builds coral reefs. Without dinoflagellate symbionts, corals lose algal pigments in a process called coral bleaching, and they eventually die. This explains why reef-building corals do not reside in waters deeper than 20 meters: Not enough light reaches those depths for dinoflagellates to photosynthesize.
Where do physical laws govern energy flow and chemical cycling?	habitats	oceans	environments	ecosystems	55.1 Physical laws govern energy flow and chemical cycling in ecosystems.
The distribution of thermal speeds depends strongly on temperature. as temperature increases, the speeds are shifted to higher values and the distribution is what?	removed	decreased	improved	broadened	The distribution of thermal speeds depends strongly on temperature. As temperature increases, the speeds are shifted to higher values and the distribution is broadened.
Carbohydrates, proteins, lipids, and nucleic acids are the four classes of what type of compounds?	chromosomal compounds	reversible compounds	nutrient compounds	biochemical compounds	Carbohydrates are one of four classes of biochemical compounds. The other three classes are proteins, lipids, and nucleic acids. In addition to cellulose, carbohydrates include sugars and starches. Carbohydrate molecules contain atoms of carbon, hydrogen, and oxygen. Living things use carbohydrates mainly for energy. For more in-depth information on carbohydrates, you may want to watch the videos at these URLs:.
What is the most important factor in soil formation?	worms	fertilizer	carbon	climate	Climate is the most important factor in soil formation. The climate of a region is the result of its temperature and rainfall. We can identify different climates by the plants that grow there ( Figure below ).
What is the outer layer of cells in a root called?	muscles	igneous	skeletal	epidermis	The root has an outer layer of cells called the epidermis, which surrounds areas of ground tissue and vascular tissue. The epidermis provides protection and helps in absorption. Root hairs, which are extensions of root epidermal cells, increase the surface area of the root, greatly contributing to the absorption of water and minerals.
What type of feeders are the largest sharks and rays?	resulting feeders	resting feeders	month feeders	suspension feeders	null
Chemical digestion couldn't take place without the help of what?	pigments	melatonin	neurotransmitters	digestive enzymes	Chemical digestion could not take place without the help of digestive enzymes. An enzyme is a protein that speeds up chemical reactions in the body. Digestive enzymes speed up chemical reactions that break down large food molecules into small molecules.
Where would you find three tiny bones called the hammer, anvil, and stirrup?	tail bone	foot	neck	middle ear	The middle ear contains three tiny bones (ossicles) called the hammer, anvil, and stirrup. If you look at these bones in the Figure above , you might notice that they resemble the objects for which they are named. The three bones transmit vibrations from the eardrum to the inner ear. The arrangement of the three bones allows them to work together as a lever that increases the amplitude of the waves as they pass to the inner ear.
Energy resources can be put into two categories — renewable or?	synthetic	reusable	precious	nonrenewable	Energy resources can be put into two categories — renewable or non-renewable. Nonrenewable resources are used faster than they can be replaced. Renewable resources can be replaced as quickly as they are used. Renewable resources may also be so abundant that running out is impossible.
Even the age of earth has been estimated on the basis of what?	gasses	membranes	tree rings	radioisotopes	Radioactive isotopes, or radioisotopes, can be used to estimate the ages of not only of rocks, but also of fossils and artifacts made long ago by human beings. Even the age of Earth has been estimated on the basis of radioisotopes. The general method is called radioactive dating . To understand how radioactive dating works, you need to understand radioisotopes and radioactive decay.
In the primary response to infection, what are secreted first from plasma cells?	pathogens	platelets	parasites	antibodies	Figure 17.18 In the primary response to infection, antibodies are secreted first from plasma cells. Upon re-exposure to the same pathogen, memory cells differentiate into antibody-secreting plasma cells that output a greater amount of antibody for a longer period of time.
A hookworm is classified as what type of organism?	bacterium	predator	virus	parasite	Parasites may live either inside or on the surface of their host. An example of a parasite is a hookworm. Hookworms are roundworms that affect the small intestine and lungs of a host organism. They live inside of humans and cause them pain. However, the hookworms must live inside of a host in order to survive. Parasites may even kill the host they live on, but then they also kill their host organism, so this is rare. Parasites are found in animals, plants, and fungi. Hookworms are common in the moist tropic and subtropic regions. There is very little risk of getting a parasite in industrialized nations.
A pigment within plant cells which absorbs light is called?	xylem	green	carbonate	chlorophyll	chlorophyll - a pigment within plant cells which absorbs light.
Where does slime mold typically live?	in the jungle	in the sea	in the soil and in glaciers	decaying plant life and in the soil	Slime molds live on decaying plant life and in the soil.
Genital warts is an sti caused by what?	human papova virus	human polyoma virus	human conoil virus	human papilloma virus	Genital warts is an STI caused by human papilloma virus (HPV), which is pictured in Figure below . This is one of the most common STIs in U. S. teens. Genital warts can’t be cured, but a vaccine can prevent most HPV infections. The vaccine is recommended for boys and girls starting at 11 or 12 years of age. It’s important to prevent HPV infections because they may lead to cancer later in life.
What do ectotherms use to regulate body temperature?	combustion energy sources	result energy sources	Flexible Energy Source	external energy sources	Ectotherms, sometimes called cold-blooded animals, do not use the energy of metabolism to regulate body temperature. Instead, they depend on external energy sources, such as sunlight. Fish, for example, will seek out water of different temperatures to regulate body temperature. The amount of energy available is directly related to the metabolic rate of the animal. When energy is scarce, ectotherms may also hibernate. The connection between metabolism and body temperature is a reminder that energy and chemical reactions are intimately related. A basic understanding of this relationship is especially important when those chemical reactions occur within our own bodies. Energy is a vital component of the world around us. Nearly every physical and chemical process, including all the chemical reactions discussed in previous chapters, occurs with a simultaneous energy change. In this chapter, we will explore the nature of energy and how energy and chemistry are related.
What event occurred at the close of the precambrian era?	natural selection	spontaneous mutation	ecosystem succession	a mass extinction	At the close of the Precambrian 544 million years ago, a mass extinction occurred. In a mass extinction , many or even most species abruptly disappear from Earth. There have been five mass extinctions in Earth’s history. Many scientists think we are currently going through a sixth mass extinction.
A balanced equation has an equal number of what on each side?	protons and reactions	electrons and neutrons	valencies and electrons	protons and neutrons	If you count the number of protons and neutrons on each side of this equation, you’ll see that the numbers are the same on both sides of the arrow. This means that the equation is balanced. The thorium-234 produced in this reaction is unstable, so it will undergo radioactive decay as well. The alpha particle produced in the reaction can pick up two electrons to form the element helium. This is how most of Earth’s helium formed.
Pure substances have a constant composition and can only be changed by what?	carbon reactions	radiation	growth	chemical reactions	Pure substances have a constant composition and can only be changed by chemical reactions. They can be classified as either elements or compounds.
Earthquakes occur most often at which natural feature?	artificial boundaries	plate holes	pattern boundaries	plate boundaries	The vast majority of earthquakes happen at plate boundaries.
How many atmospheric circulation cells are there?	five	three	two	six	The globe has six atmospheric circulation cells. Three are north of the Equator and three are south. These cells have names.
Proper chemical formulas for ionic compounds balance the total positive charge with what?	total atomic charge	total electric charge	total ionic charge	total negative charge	Proper chemical formulas for ionic compounds balance the total positive charge with the total negative charge.
Which process helps microorganisms make food with chemicals pouring out of deep-sea vents?	synaptogenesis	photosynthesis	biosynthesis	chemosynthesis	There are many more organisms around deep-sea vents. Microorganisms use chemicals that pour out of the vents to make food by chemosynthesis. These producers support large numbers of other organisms, including crustaceans and red tubeworms like those pictured in Figure below .
What is a combination of two or more substances in any proportion called?	solvent	combination	solution	mixture	Not all combined substances are compounds. Some are mixtures. A mixture is a combination of two or more substances in any proportion. The substances in a mixture may be elements or compounds. The substances don’t combine chemically to form a new substance, as they do in a compound. Instead, they keep their original properties and just intermix. Examples of mixtures include salt and water in the ocean and gases in the atmosphere. Other examples are pictured in Figure below .
Where is the youngest seafloor located?	at the floor	at the base	at the reefs	at the ridge	The youngest seafloor is at the ridge. The oldest is farthest from the ridge. The oldest seafloor is much younger than the oldest continent.
What kind of mixture consists of two or more phases, exemplified when a combination of oil and water forms layers?	complex miture	homogeneous	simple mixture	heterogeneous	A phase is any part of a sample that has a uniform composition and properties. By definition, a pure substance or a homogeneous mixture consists of a single phase. A heterogeneous mixture consists of two or more phases. When oil and water are combined, they do not mix evenly, but instead form two separate layers. Each of the layers is called a phase.
The values of strangeness assigned to various particles are based on what?	penetration potential	atomic mass	thermal energy	decay systematics	lifetimes on the order of 10 s (the exception is Σ , whose short lifetime is explained by its particular quark substructure. ), implying that their decay is caused by the weak force alone, although they are hadrons and feel the strong force. The decay modes of these particles also show patterns—in particular, certain decays that should be possible within all the known conservation laws do not occur. Whenever something is possible in physics, it will happen. If something does not happen, it is forbidden by a rule. All this seemed strange to those studying these particles when they were first discovered, so they named a new quantum number strangeness, given the symbol S in the table given above. The values of strangeness assigned to various particles are based on the decay systematics. It is found that strangeness is conserved by the strong force, which.
Together, the muscular and skeletal organs are known as what?	nervous system	lymphatic system	cardiovascular system	musculoskeletal system	CHAPTER REVIEW 6.1 The Functions of the Skeletal System The major functions of the bones are body support, facilitation of movement, protection of internal organs, storage of minerals and fat, and hematopoiesis. Together, the muscular system and skeletal system are known as the musculoskeletal system.
What do factories and power plants use to remove particulates and waste gases from exhaust before releasing it?	catalytic converters	compressors	mufflers	scrubbers	Scrubbers are used in factories and power plants. They remove particulates and waste gases from exhaust before it is released to the air. You can see how a scrubber works in Figure below .
Humans typically have how many pairs of chromosomes?	25 pairs	14 pairs	17 pairs	23 pairs	No, you only received half of your mother's chromosomes and half of your father's chromosomes. If you inherited them all, you would have twice the number of chromosomes that you're supposed to have. Humans typically have 23 pairs of chromosomes. If you received all your parents' chromosomes, you would have 46 pairs!.
Correlation is different from what term that refers to the factor that is producing the effect?	differentiation	manifestation	correlation	causation	But correlation does not necessarily indicate causation. Causation refers to the factor that is producing the effect. If I push a toy car, I will cause it to move. To explain the difference between correlation and causation, let’s look at an example. Sugar consumption in the United States has been rising for decades ( Figure below ). There is a positive correlation between sugar consumption and rising average global temperatures.
What organelles do animal cells use to convert food into energy?	flagellum	endoplasmic reticulum	nucleus	mitochondria	When an animal needs energy, it eats food. That's why animals use mitochondria to convert food into energy. Plants, on the other hand, don't seem to eat anything. Instead, they receive energy from water and sunlight. They use chloroplasts to convert light into energy through photosynthesis. The focus of this concept is to delineate the distinct differences between plant and animal cells.
Where does egg production happen?	testes	uterus	fallopian tube	ovaries	Egg production takes place in the ovaries. It takes several steps to make an egg:.
What can be used to estimate the energy change of a chemical reaction?	isoenergies	bond magnitudes	chemical energy	bond energies	Bond energies can be used to estimate the energy change of a chemical reaction. When bonds are broken in the reactants, the energy change for this process is endothermic. When bonds are formed in the products, the energy change for this process is exothermic. We combine the positive energy change with the negative energy change to estimate the overall energy change of the reaction. For example, in.
Destructive interference occurs when two identical waves are superimposed exactly out of phase. a standing wave is one in which two waves superimpose to produce a wave that varies in amplitude but does not do this?	reproduce	substrate	membrane	propagate	Superposition is the combination of two waves at the same location. Constructive interference occurs when two identical waves are superimposed in phase. Destructive interference occurs when two identical waves are superimposed exactly out of phase. A standing wave is one in which two waves superimpose to produce a wave that varies in amplitude but does not propagate. Nodes are points of no motion in standing waves. An antinode is the location of maximum amplitude of a standing wave. Waves on a string are resonant standing waves with a fundamental frequency and can occur at higher multiples of the fundamental, called overtones or harmonics. Beats occur when waves of similar frequencies f 1 and f 2 are superimposed. The resulting amplitude oscillates with a beat frequency given by.
What is the layer outside the cell wall in a prokaryote?	membrane	rim	pod	capsule	Many prokaryotes have another layer, called a capsule, outside the cell wall. The capsule protects the cell from chemicals and drying out. It also allows the cell to stick to surfaces and to other cells.
What delivers natural gas from rock that might not otherwise be obtainable?	grinding	rippling	drilling	fracking	Fracking delivers natural gas from rock that might not otherwise be obtainable.
Name the white blood cells that can squeeze through capillary walls and swallow particles.	hemoglobin	platelets	lymphocytes	neutrophils	Neutrophils are WBCs that can squeeze through capillary walls and swallow particles such as bacteria and parasites.
Permanent dipole-dipole interactions are found in what kind of molecules?	geologic	directional	dual	polar	Polar molecules have permanent dipole-dipole interactions.
The energy released during an earthquake is called what?	tidal	radiation	hydro	magnitude	The ways seismologists measure an earthquake have changed over the decades. Initially, they could only measure what people felt and saw, the intensity. Now they can measure the energy released during the quake, the magnitude.
Many replication forks develop along a what?	allele	nucleus	genome	chromosome	Many replication forks develop along a chromosome. This process continues until the replication forks meet, and the all of the DNA in a chromosome has been copied. Each new strand that has formed is complementary to the strand used as the template. Each resulting DNA molecule is identical to the original DNA molecule. During prophase of mitosis or prophase I of meiosis, these molecules of DNA condense into a chromosome made of two identical "sister" chromatids. This process ensures that cells that result from cell division have identical sets of genetic material, and that the DNA is an exact copy of the parent cell’s DNA.
What is the term for the strength of an acid or base?	texture	carbon	pH	acidity	The strength of an acid or base is called acidity. It depends on how much of the substance breaks down into ions when it dissolves in water.
A bog is a type of ____	stream	plant	lake	wetland	Not all wetlands are alike, as you can see below ( Figure below ). Wetlands vary in how wet they are and how much of the year they are soaked. Wetlands also vary in the kinds of plants that live in them. This depends mostly on the climate where the wetland is found. Types of wetlands include marshes, swamps, and bogs.
In projectile motion, the horizontal displacement of an object is called its what?	variety	width	height	range	In projectile motion, the horizontal displacement of an object is called its range .
An oil drop is stationary when what downward force exactly equals the upward electrical force on the drop?	radiation	magnetic	newtonian	gravitational	The charge on the plates is adjustable. By measuring the terminal velocity of the oil drops with the electric field off, Millikan could determine the mass of the drops. Millikan and his graduate assistant were able to determine the force of the field on the drops when it was turned on by comparing the velocity of the drops with the field on to their velocity with the field off. This is easily determined when the oil drop is stationary; namely, when the downward gravitational force exactly equals the upward electrical force on the drop.
The secretion of what may influence the body’s circadian rhythms?	serotonin	human growth hormone	testosterone	melatonin	The secretion of melatonin may influence the body’s circadian rhythms, the dark-light fluctuations that affect not only sleepiness and wakefulness, but also appetite and body temperature. Interestingly, children have higher melatonin levels than adults, which may prevent the release of gonadotropins from the anterior pituitary, thereby inhibiting the onset of puberty. Finally, an antioxidant role of melatonin is the subject of current research. Jet lag occurs when a person travels across several time zones and feels sleepy during the day or wakeful at night. Traveling across multiple time zones significantly disturbs the light-dark cycle regulated by melatonin. It can take up to several days for melatonin synthesis to adjust to the light-dark patterns in the new environment, resulting in jet lag. Some air travelers take melatonin supplements to induce sleep.
Photosynthesis takes the energy of sunlight and combines water and carbon dioxide to produce sugar and oxygen as this?	primary product	secondary product	reactive product	waste product	The free electron travels through the electron transport chain, and the energy of the electron is used to pump hydrogen ions into the thylakoid space, transferring the energy into the electrochemical gradient. The energy of the electrochemical gradient is used to power ATP synthase, and the energy is transferred into a bond in the ATP molecule. In addition, energy from another photon can be used to create a high-energy bond in the molecule NADPH. 16 Photosynthesis takes the energy of sunlight and combines water and carbon dioxide to produce sugar and oxygen as a waste product. The reactions of respiration take sugar and consume oxygen to break it down into carbon dioxide and water, releasing energy. Thus, the reactants of photosynthesis are the products of respiration, and vice versa.
Purkinje fibers have a fast inherent what?	induction rate	replication rate	electromagnetic rate	conduction rate	Atrioventricular Bundle (Bundle of His), Bundle Branches, and Purkinje Fibers Arising from the AV node, the atrioventricular bundle, or bundle of His, proceeds through the interventricular septum before dividing into two atrioventricular bundle branches, commonly called the left and right bundle branches. The left bundle branch has two fascicles. The left bundle branch supplies the left ventricle, and the right bundle branch the right ventricle. Since the left ventricle is much larger than the right, the left bundle branch is also considerably larger than the right. Portions of the right bundle branch are found in the moderator band and supply the right papillary muscles. Because of this connection, each papillary muscle receives the impulse at approximately the same time, so they begin to contract simultaneously just prior to the remainder of the myocardial contractile cells of the ventricles. This is believed to allow tension to develop on the chordae tendineae prior to right ventricular contraction. There is no corresponding moderator band on the left. Both bundle branches descend and reach the apex of the heart where they connect with the Purkinje fibers (see Figure 19.19, step 4). This passage takes approximately 25 ms. The Purkinje fibers are additional myocardial conductive fibers that spread the impulse to the myocardial contractile cells in the ventricles. They extend throughout the myocardium from the apex of the heart toward the atrioventricular septum and the base of the heart. The Purkinje fibers have a fast inherent conduction rate, and the electrical impulse reaches all of the ventricular muscle cells in about 75 ms (see Figure 19.19, step 5). Since the electrical stimulus begins at the apex, the contraction also begins at the apex and travels toward the base of the heart, similar to squeezing a tube of toothpaste from the bottom. This allows the blood to be pumped out of the ventricles and into the aorta and pulmonary trunk. The total time elapsed from the initiation of the impulse in the SA node until depolarization of the ventricles is approximately 225 ms.
What process affecting genes or chromosomes causes genetic disorders?	graduation	radiation	infection	mutation	Many genetic disorders are caused by mutations in one or a few genes. Others are caused by chromosomal mutations. Some human genetic disorders are X-linked or Y-linked, which means the faulty gene is carried on these sex chromosomes. Other genetic disorders are carried on one of the other 22 pairs of chromosomes; these chromosomes are known as autosomes or autosomal (non-sex) chromosomes. Some genetic disorders are due to new mutations, others can be inherited from your parents.
What type of engine burns fuel to heat water and produce steam?	conduction	convection	condensation	combustion	An external combustion engine burns fuel to heat water and produce steam. The steam is under pressure and is used to push a piston back and forth inside a cylinder. As the piston moves back and forth, it moves a piston rod, which can do work.
Oncogenesis is one name for the process where normal cells turn into what?	blood cells	lung cells	brain cells	cancer cells	Carcinogenesis is the process by which normal cells are transformed into cancer cells. The process is also known as oncogenesis or tumorigenesis and it depends on both the activation of oncogenes and deactivation of tumor suppressor genes . Proto-oncogenes, the non-cancerous normal version of an oncogene, can be a transcription factor like c-fos, c-jun and c-myc, or a gene whose product is involved in signal transduction, leading to altered gene expression. When mutations cause the regulation of this process to be disturbed, cell proliferation can be enhanced leading to tumorigenesis.
Characteristics of an organism are passed from one generation to the next through what?	eggs	ribosomes	sperm	genes	Characteristics of organisms are passed from one generation to the next through their genes.
Reactants are substances that start what?	consumption reaction	growth reaction	dying reaction	chemical reaction	Reactants are substances that start a chemical reaction.
What are cyclic compounds which have an element other than carbon atoms in the ring?	polymeric compounds	axial compounds	homocyclic compounds	heterocyclic compounds	Note So far we have studied only aromatic compounds with carbon-containing rings. However, many cyclic compounds have an element other than carbon atoms in the ring. These compounds, called heterocyclic compounds, are discussed inChapter 15 "Organic Acids and Bases and Some of Their Derivatives", Section 15.13 "Amines as Bases". Some of these are heterocyclic aromatic compounds. Table 13.4 Some Drugs That Contain a Benzene Ring.
Surviving megaspores develop into what?	singular celled female gametophytes	multicellular male gametophytes	null gametophytes	multicellular female gametophytes	null
Stoichiometry is concerned with the reactants and the products in chemical what?	solvents	photosynthesis	bonds	reactions	numerical relationships between the reactants and the products in balanced chemical reactions is called stoichiometry.
What do you call the angle at which waves strike a wall?	incidence impact	rotation of incidence	angle of impact	angle of incidence	Waves strike a wall at an angle, called the angle of incidence. The waves are reflected at the same angle, called the angle of reflection, but in a different direction. Both angles are measured relative to a line that is perpendicular to the wall.
Nitrogen & sulfur oxide combine with rain to form what?	coarse rain	toxic rain	steam rain	acid rain	Nitrogen and sulfur oxides combine with rain to form acid rain.
The nitrogenous bases found in nucleotides are classified as pyrimidines or what?	Science	Fallen	terpenes	purines	The nitrogenous bases found in nucleotides are classified as pyrimidines or purines. Pyrimidines are heterocyclic amines with two nitrogen atoms in a six-member ring and include uracil, thymine, and cytosine. (For more information about heterocyclic amines, see Chapter 15 "Organic Acids and Bases and Some of Their Derivatives", Section 15.13 "Amines as Bases". ) Purines are heterocyclic amines consisting of a pyrimidine ring fused to a five-member ring with two nitrogen atoms. Adenine and guanine are the major purines found in nucleic acids (Figure 19.2 "The Nitrogenous Bases Found in DNA and RNA"). Figure 19.2 The Nitrogenous Bases Found in DNA and RNA.
Instead of heat, organisms use what to speed up reactions?	synthesis	metabolism	acids	catalysis	null
What term in science describes not just a guess, but a well-formed set of explanations for a phenomenon?	evolution	hypothesis	concept	theory	Some ideas in science gain the status of theories. Scientists use the term "theory" differently than it is used in everyday language. You might say, "I think the dog ate my homework, but it’s just a theory. " In other words, it’s just one of many possible explanations for the missing work. However, in science, a theory is much more than that.
Although helper t cells do not destroy infected or damaged body cells, they are still necessary for what?	lung response	brain response	mutations response	immune response	Helper T cells do not destroy infected or damaged body cells. But they are still necessary for an immune response. They help by releasing chemicals that control other lymphocytes. The chemicals released by helper T cells “switch on” both B cells and killer T cells so they can recognize and fight specific pathogens.
The seven unique crystal types are defined by what parts of themselves (parts that intersect at various angles)?	eyes	shards	angles	faces	Crystals are classified into general categories based on their shapes. A crystal is defined by its faces, which intersect with one another at specific angles, which are characteristic of the given substance. The seven crystal systems are shown below, along with an example of each. The edge lengths of a crystal are represented by the letters , , and . The angles at which the faces intersect are represented by the Greek letters , , and . Each of the seven crystal systems differs in terms of the angles between the faces and in the number of edges of equal length on each face.
In their processes of gene expression, archael cells show similarties to both bacterial cells and which other type of cell?	plant cells	Prokaryotic	chloroplasts	eukaryotic	null
What term refers to the amount of solute that can dissolve in a given amount of solvent at a given temperature?	turbidity	viscosity	saturation	solubility	Solubility is the amount of solute that can dissolve in a given amount of solvent at a given temperature. Some solutes have greater solubility than others.
Although quite different, beryllium, magnesium, calcium, strontium, barium, and radium are all classified as what type of metals?	acidic earth metals	mucous earth metals	detergent earth metals	alkaline earth metals	The Alkaline Earth Metals The alkaline earth metals are beryllium, magnesium, calcium, strontium, barium, and radium. Beryllium, strontium, and barium are rather rare, and radium is unstable and highly radioactive. In contrast, calcium and magnesium are the fifth and sixth most abundant elements on Earth, respectively; they are found in huge deposits of limestone and other minerals.
What predatory mammal is the fastest land animal on earth?	giraffe	panther	tiger	cheetah	Mammals are noted for the many ways they can move about. Generally, their limbs are very mobile. Often, they can be rotated. Many mammals are also known for their speed. The fastest land animal is a predatory mammal. Can you guess what it is? Racing at speeds of up to 112 kilometers (70 miles) per hour, the cheetah wins hands down. In addition, the limbs of mammals let them hold their body up above the ground. That’s because the limbs are attached beneath the body, rather than at the sides as in reptiles (see Figure below ).
Why did woolly mammoths began to go extinct thousands of years ago?	competition for food	volcanic eruptions	parasites	hunting by humans	Woolly mammoths began to go extinct about 10,000 years ago, soon after paleontologists believe humans able to hunt them began to colonize North America and northern Eurasia (Figure 19.8). A mammoth population survived on Wrangel Island, in the East Siberian Sea, and was isolated from human contact until as recently as 1700 BC. We know a lot about these animals from carcasses found frozen in the ice of Siberia and other northern regions. It is commonly thought that climate change and human hunting led to their extinction. A 2008 study estimated that climate change reduced the mammoth’s range from 3,000,000 square miles 42,000 years [3] ago to 310,000 square miles 6,000 years ago. Through archaeological evidence of kill sites, it is also well documented that humans hunted these animals. A 2012 study concluded that no single factor was [4] exclusively responsible for the extinction of these magnificent creatures. In addition to climate change and reduction of habitat, scientists demonstrated another important factor in the mammoth’s extinction was the migration of human hunters across the Bering Strait to North America during the last ice age 20,000 years ago. The maintenance of stable populations was and is very complex, with many interacting factors determining the outcome. It is important to remember that humans are also part of nature. Once we contributed to a species’ decline using primitive hunting technology only.
What is a developing baby called in the very early stages?	sperm	fetus	uterus	embryo	While a woman is pregnant, the developing baby may be called an embryo or a fetus. Do these mean the same thing? No, in the very early stages the developing baby is called an embryo, while in the later stages it is called a fetus. When the ball of cells first implants into the uterus, it is called an embryo . The embryo stage lasts until the end of the 8 th week after fertilization. After that point until birth, the developing baby is called a fetus .
What is released when an atom gains valence electrons and forms a negative ion?	fusion	charge	heat	energy	It takes energy to remove valence electrons from an atom and form a positive ion. Energy is released when an atom gains valence electrons and forms a negative ion.

What series of reactions is common to fermentation and cellular respiration?

photosynthesis

spermatogenesis

metabolism

glycolysis

null

In which ways may sponges reproduce?

meiosis and mitosis

sexually and vertically

internally and externally

sexually and asexually

The sponge life cycle includes sexual reproduction. Sponges may also reproduce asexually.

What do barnacles anchor to?

scales

eggs

fossils

rocks

Mo Riza. Barnacles are adapted to the intertidal zone by anchoring to rocks . CC BY 2.0.

Organic compounds produced by what process provide the energy and building material for ecosystems?

glycolysis

cyclogenesis

nuclear fusion

photosynthesis

null

As you increase the temperature of a liquid what happens to the solubility of a solute?

viscosity increases

turbidity increases

hydrophilic increases

solubility increases

Temperature affects the solubility of a solute. However, it affects the solubility of gases differently than the solubility of solids and liquids.

The relative sizes of the atoms show several trends with regard to what visual method of organization?

oscillations table

vibrations table

chemistry table

periodic table

The relative sizes of the atoms show several trends with regard to the structure of the periodic table. Atoms become larger going down a column and smaller going across a period.

Toward the end of pregnancy, the synthesis of oxytocin receptors in what reproductive organ increases?

lungs

stomach

liver

uterus

Oxytocin When fetal development is complete, the peptide-derived hormone oxytocin (tocia- = “childbirth”) stimulates uterine contractions and dilation of the cervix. Throughout most of pregnancy, oxytocin hormone receptors are not expressed at high levels in the uterus. Toward the end of pregnancy, the synthesis of oxytocin receptors in the uterus increases, and the smooth.

If an animal eats large pieces of food it is known as a?

bulk producer

large consumer

many feeder

bulk feeder

null

What are the two vibrating fields that electromagnetic waves consist of?

radioactive and magnetic

flammable and magnetic

magnetic and mechanical

electric and magnetic

Electromagnetic waves are waves that consist of vibrating electric and magnetic fields. They transfer energy through matter or across space. The transfer of energy by electromagnetic waves is called electromagnetic radiation.

What is the process by which plants and animals increase in size?

activity

birth

reproduction

growth

null

How do endocrine hormones travel throughout the body?

in the lymph

in urea

in mucus

in the blood

Endocrine hormones travel throughout the body in the blood. However, each endocrine hormone affects only certain cells, called target cells.

The post-anal tail is at the end of the organism opposite what?

fingers

legs

knees

head

The post-anal tail is at the end of the organism opposite the head. It extends beyond the anus.

What is the term for the moles of solute divided by the kilograms of solvent?

kilocalorie

molar solvency

molar weight

molality

A final way to express the concentration of a solution is by its molality. The molality ( m ) of a solution is the moles of solute divided by the kilograms of solvent. A solution that contains 1.0 mol of NaCl dissolved into 1.0 kg of water is a “one-molal” solution of sodium chloride. The symbol for molality is a lower-case m written in italics.

Active transport moves substances from an area of lower concentration to an area of?

the same concentration

flat concentration

low concentration

higher concentration

Active transport requires energy because it moves substances from an area of lower to higher concentration. An example is the sodium-potassium pump. Another form of active transport is vesicle transport, which is needed for very large molecules.

How does the skin eliminates excess water and salts?

burn

peel

itch

sweat

The skin eliminates excess water and salts in sweat.

Organophosphates typically interfere with nerve signal transmission by inhibiting the enzymes that degrade what?

protein molecules

prototype molecules

potassium molecules

transmitter molecules

null

What is the horizontal distance between two waves, measured at a common point (crest to crest or trough to trough), called?

frequency

linear

absorption

wavelength

Seismic waves are just one type of wave. Sound and light also travel in waves. Every wave has a high point called a crest and a low point called a trough . The height of a wave from the center line to its crest is its amplitude . The horizontal distance between waves from crest to crest (or trough to trough) is its wavelength ( Figure below ).

Steroid hormones, such as cortisol and ecdysteroid, are lipids that contain four fused what?

oxide rings

acid rings

nitrogen rings

carbon rings

null

The solubility of gases, liquids, and solids are affected by changes in what?

volume

elevation

friction

temperature

The solubility of gases, liquids, and solids are affected by changes in temperature.

Only animals have muscle tissue and what other type of tissue?

cartilage

nonvascular tissue

vascular tissue

nervous

23.29 Characteristics of an Animal • There is no one universally accepted definition of an animal. The following treatment follows your text, beginning on page 876. • Animals: • Are multicellular, heterotrophic eukaryotes . • Lack the distinctive cell walls of plants & fungi • Share unique characteristics . • Share certain reproductive characteristics . • Other commonly used definitions . Animals are multicellular heterotrophic eukaryotes • Unfortunately, none of these traits is exclusive to animals: • Plants, fungi, and some algae are multicellular. • Many bacteria, protists, and all fungi are heterotrophic. • Everything other than bacteria and archaea are eukaryotic. • Moreover, all three of these characteristics also apply to fungi. • However, there is a difference here between animals and fungi. Animals generally take in their food through ingestion, or eating and swallowing something. Fungi are absorptive heterotrophs; they secrete their digestive enzymes onto their food, and then absorb the resulting nutrients. Animals share unique characteristics • Only animals have muscle tissue and nervous tissue. • Only animals have collagen, a structural protein • Only animals have the following types of intercellular junctions: (See pages 135 - 139, Figure 7.15 in your text for more information on these junctions.

What type of matter transmits light but scatters the light as it passes through?

a mirror

opaque matter

refractive matter

translucent matter

Translucent matter is matter that transmits light but scatters the light as it passes through. Light passes through translucent objects but you cannot see clearly through them because the light is scattered in all directions. The frosted glass panes at the bottom of the window above are translucent.

During an earthquake, the ground shakes as stored up energy is released from what?

grass

fossils

the soil

rocks

During an earthquake, the ground shakes as stored up energy is released from rocks.

Tunnel vision involves the loss of what visual fields?

underwater

distant

quickly-moving

peripheral

A unique clinical presentation that relates to this anatomic arrangement is the loss of lateral peripheral vision, known as bilateral hemianopia. This is different from “tunnel vision” because the superior and inferior peripheral fields are not lost. Visual field deficits can be disturbing for a patient, but in this case, the cause is not within the visual system itself. A growth of the pituitary gland presses against the optic chiasm and interferes with signal transmission. However, the axons projecting to the same side of the brain are unaffected. Therefore, the patient loses the outermost areas of their field of vision and cannot see objects to their right and left. Extending from the optic chiasm, the axons of the visual system are referred to as the optic tract instead of the optic nerve. The optic tract has three major targets, two in the diencephalon and one in the midbrain. The connection between the eyes and diencephalon is demonstrated during development, in which the neural tissue of the retina differentiates from that of the diencephalon by the growth of the secondary vesicles. The connections of the retina into the CNS are a holdover from this developmental association. The majority of the connections of the optic tract are to the thalamus—specifically, the lateral geniculate nucleus. Axons from this nucleus then project to the visual cortex of the cerebrum, located in the occipital lobe. Another target of the optic tract is the superior colliculus. In addition, a very small number of RGC axons project from the optic chiasm to the suprachiasmatic nucleus of the hypothalamus. These RGCs are photosensitive, in that they respond to the presence or absence of light. Unlike the photoreceptors, however, these photosensitive RGCs cannot be used to perceive images. By simply responding to the absence or presence of light, these RGCs can send information about day length. The perceived proportion of sunlight to darkness establishes the circadian rhythm of our bodies, allowing certain physiological events to occur at approximately the same time every day.

Systemic mycoses spread to internal organs, most commonly entering the body through this?

infestation system

digestive system

skeletal system

respiratory system

Systemic mycoses spread to internal organs, most commonly entering the body through the respiratory system. For example, coccidioidomycosis (valley fever) is commonly found in the southwestern United States, where the fungus resides in the dust. Once inhaled, the spores develop in the lungs and cause symptoms similar to those of tuberculosis. Histoplasmosis is caused by the dimorphic fungus Histoplasma capsulatum. It also causes pulmonary infections, and in rarer cases, swelling of the membranes of the brain and spinal cord. Treatment of these and many other fungal diseases requires the use of antifungal medications that have serious side effects. Opportunistic mycoses are fungal infections that are either common in all environments, or part of the normal biota. They mainly affect individuals who have a compromised immune system. Patients in the late stages of AIDS suffer from opportunistic mycoses that can be life threatening. The yeast Candida sp. , a common member of the natural biota, can grow unchecked and infect the vagina or mouth (oral thrush) if the pH of the surrounding environment, the person’s immune defenses, or the normal population of bacteria are altered. Mycetismus can occur when poisonous mushrooms are eaten. It causes a number of human fatalities during mushroompicking season. Many edible fruiting bodies of fungi resemble highly poisonous relatives, and amateur mushroom hunters are cautioned to carefully inspect their harvest and avoid eating mushrooms of doubtful origin. The adage “there are bold mushroom pickers and old mushroom pickers, but are there no old, bold mushroom pickers” is unfortunately true.

The three features that are unique to the large intestine are the teniae coli, haustra, and what?

binary appendages

radial appendages

disc appendages

epiploic appendages

Anatomy Three features are unique to the large intestine: teniae coli, haustra, and epiploic appendages (Figure 23.23). The teniae coli are three bands of smooth muscle that make up the longitudinal muscle layer of the muscularis of the large intestine, except at its terminal end. Tonic contractions of the teniae coli bunch up the colon into a succession of pouches called haustra (singular = hostrum), which are responsible for the wrinkled appearance of the colon. Attached to the teniae coli are small, fat-filled sacs of visceral peritoneum called epiploic appendages. The purpose of these is unknown. Although the rectum and anal canal have neither teniae coli nor haustra, they do have well-developed layers of muscularis that create the strong contractions needed for defecation.

Most living things build proteins from the same 20 different what?

acid peptides

uncommon acids

atomic isolates

amino acids

if the salt produced is an acidic salt.

What reaction, along with photosynthesis, provides energy to the vast majority of living things?

Internal Respiration

devices respiration

primarily respiration

cellular respiration

The chemical reactions of photosynthesis and cellular respiration together provide energy to virtually all living things on Earth.

Some animals increase body fat in winter to stay?

cold

thin

aware

warm

null

Coal, oil, and natural gas are examples of what, which forms when organic matter is under pressure for millions of years?

nuclear fission

complex carbohydrates

solar fuels

fossil fuels

Millions of years ago, there were so many dead plants and animals that they could not completely decompose before they were buried. They were covered over by soil or sand, tar or ice. These dead plants and animals are organic matter made out of cells full of carbon-containing organic compounds (carbohydrates, lipids, proteins and nucleic acids). What happened to all this carbon? When organic matter is under pressure for millions of years, it forms fossil fuels. Fossil fuels are coal, oil, and natural gas.

Protists play critically important ecological roles as producers and, on the other end of food webs, as what?

probiotics

dissolvers

absorbers

decomposers

Beneficial Protists Protists play critically important ecological roles as producers particularly in the world’s oceans. They are equally important on the other end of food webs as decomposers. Protists as Food Sources Protists are essential sources of nutrition for many other organisms. In some cases, as in plankton, protists are consumed directly. Alternatively, photosynthetic protists serve as producers of nutrition for other organisms by carbon fixation. For instance, photosynthetic dinoflagellates called zooxanthellae pass on most of their energy to the coral polyps that house them (Figure 13.19). In this mutually beneficial relationship, the polyps provide a protective environment and nutrients for the zooxanthellae. The polyps secrete the calcium carbonate that builds coral reefs. Without dinoflagellate symbionts, corals lose algal pigments in a process called coral bleaching, and they eventually die. This explains why reef-building corals do not reside in waters deeper than 20 meters: Not enough light reaches those depths for dinoflagellates to photosynthesize.

Where do physical laws govern energy flow and chemical cycling?

habitats

oceans

environments

ecosystems

55.1 Physical laws govern energy flow and chemical cycling in ecosystems.

The distribution of thermal speeds depends strongly on temperature. as temperature increases, the speeds are shifted to higher values and the distribution is what?

removed

decreased

improved

broadened

The distribution of thermal speeds depends strongly on temperature. As temperature increases, the speeds are shifted to higher values and the distribution is broadened.

Carbohydrates, proteins, lipids, and nucleic acids are the four classes of what type of compounds?

chromosomal compounds

reversible compounds

nutrient compounds

biochemical compounds

Carbohydrates are one of four classes of biochemical compounds. The other three classes are proteins, lipids, and nucleic acids. In addition to cellulose, carbohydrates include sugars and starches. Carbohydrate molecules contain atoms of carbon, hydrogen, and oxygen. Living things use carbohydrates mainly for energy. For more in-depth information on carbohydrates, you may want to watch the videos at these URLs:.

What is the most important factor in soil formation?

worms

fertilizer

carbon

climate

Climate is the most important factor in soil formation. The climate of a region is the result of its temperature and rainfall. We can identify different climates by the plants that grow there ( Figure below ).

What is the outer layer of cells in a root called?

muscles

igneous

skeletal

epidermis

The root has an outer layer of cells called the epidermis, which surrounds areas of ground tissue and vascular tissue. The epidermis provides protection and helps in absorption. Root hairs, which are extensions of root epidermal cells, increase the surface area of the root, greatly contributing to the absorption of water and minerals.

What type of feeders are the largest sharks and rays?

resulting feeders

resting feeders

month feeders

suspension feeders

null

Chemical digestion couldn't take place without the help of what?

pigments

melatonin

neurotransmitters

digestive enzymes

Chemical digestion could not take place without the help of digestive enzymes. An enzyme is a protein that speeds up chemical reactions in the body. Digestive enzymes speed up chemical reactions that break down large food molecules into small molecules.

Where would you find three tiny bones called the hammer, anvil, and stirrup?

tail bone

foot

neck

middle ear

The middle ear contains three tiny bones (ossicles) called the hammer, anvil, and stirrup. If you look at these bones in the Figure above , you might notice that they resemble the objects for which they are named. The three bones transmit vibrations from the eardrum to the inner ear. The arrangement of the three bones allows them to work together as a lever that increases the amplitude of the waves as they pass to the inner ear.

Energy resources can be put into two categories — renewable or?

synthetic

reusable

precious

nonrenewable

Energy resources can be put into two categories — renewable or non-renewable. Nonrenewable resources are used faster than they can be replaced. Renewable resources can be replaced as quickly as they are used. Renewable resources may also be so abundant that running out is impossible.

Even the age of earth has been estimated on the basis of what?

gasses

membranes

tree rings

radioisotopes

Radioactive isotopes, or radioisotopes, can be used to estimate the ages of not only of rocks, but also of fossils and artifacts made long ago by human beings. Even the age of Earth has been estimated on the basis of radioisotopes. The general method is called radioactive dating . To understand how radioactive dating works, you need to understand radioisotopes and radioactive decay.

In the primary response to infection, what are secreted first from plasma cells?

pathogens

platelets

parasites

antibodies

Figure 17.18 In the primary response to infection, antibodies are secreted first from plasma cells. Upon re-exposure to the same pathogen, memory cells differentiate into antibody-secreting plasma cells that output a greater amount of antibody for a longer period of time.

A hookworm is classified as what type of organism?

bacterium

predator

virus

parasite

Parasites may live either inside or on the surface of their host. An example of a parasite is a hookworm. Hookworms are roundworms that affect the small intestine and lungs of a host organism. They live inside of humans and cause them pain. However, the hookworms must live inside of a host in order to survive. Parasites may even kill the host they live on, but then they also kill their host organism, so this is rare. Parasites are found in animals, plants, and fungi. Hookworms are common in the moist tropic and subtropic regions. There is very little risk of getting a parasite in industrialized nations.

A pigment within plant cells which absorbs light is called?

xylem

green

carbonate

chlorophyll

chlorophyll - a pigment within plant cells which absorbs light.

Where does slime mold typically live?

in the jungle

in the sea

in the soil and in glaciers

decaying plant life and in the soil

Slime molds live on decaying plant life and in the soil.

Genital warts is an sti caused by what?

human papova virus

human polyoma virus

human conoil virus

human papilloma virus

Genital warts is an STI caused by human papilloma virus (HPV), which is pictured in Figure below . This is one of the most common STIs in U. S. teens. Genital warts can’t be cured, but a vaccine can prevent most HPV infections. The vaccine is recommended for boys and girls starting at 11 or 12 years of age. It’s important to prevent HPV infections because they may lead to cancer later in life.

What do ectotherms use to regulate body temperature?

combustion energy sources

result energy sources

Flexible Energy Source

external energy sources

Ectotherms, sometimes called cold-blooded animals, do not use the energy of metabolism to regulate body temperature. Instead, they depend on external energy sources, such as sunlight. Fish, for example, will seek out water of different temperatures to regulate body temperature. The amount of energy available is directly related to the metabolic rate of the animal. When energy is scarce, ectotherms may also hibernate. The connection between metabolism and body temperature is a reminder that energy and chemical reactions are intimately related. A basic understanding of this relationship is especially important when those chemical reactions occur within our own bodies. Energy is a vital component of the world around us. Nearly every physical and chemical process, including all the chemical reactions discussed in previous chapters, occurs with a simultaneous energy change. In this chapter, we will explore the nature of energy and how energy and chemistry are related.

What event occurred at the close of the precambrian era?

natural selection

spontaneous mutation

ecosystem succession

a mass extinction

At the close of the Precambrian 544 million years ago, a mass extinction occurred. In a mass extinction , many or even most species abruptly disappear from Earth. There have been five mass extinctions in Earth’s history. Many scientists think we are currently going through a sixth mass extinction.

A balanced equation has an equal number of what on each side?

protons and reactions

electrons and neutrons

valencies and electrons

protons and neutrons

If you count the number of protons and neutrons on each side of this equation, you’ll see that the numbers are the same on both sides of the arrow. This means that the equation is balanced. The thorium-234 produced in this reaction is unstable, so it will undergo radioactive decay as well. The alpha particle produced in the reaction can pick up two electrons to form the element helium. This is how most of Earth’s helium formed.

Pure substances have a constant composition and can only be changed by what?

carbon reactions

radiation

growth

chemical reactions

Pure substances have a constant composition and can only be changed by chemical reactions. They can be classified as either elements or compounds.

Earthquakes occur most often at which natural feature?

artificial boundaries

plate holes

pattern boundaries

plate boundaries

The vast majority of earthquakes happen at plate boundaries.

How many atmospheric circulation cells are there?

five

three

two

six

The globe has six atmospheric circulation cells. Three are north of the Equator and three are south. These cells have names.

Proper chemical formulas for ionic compounds balance the total positive charge with what?

total atomic charge

total electric charge

total ionic charge

total negative charge

Proper chemical formulas for ionic compounds balance the total positive charge with the total negative charge.

Which process helps microorganisms make food with chemicals pouring out of deep-sea vents?

synaptogenesis

photosynthesis

biosynthesis

chemosynthesis

There are many more organisms around deep-sea vents. Microorganisms use chemicals that pour out of the vents to make food by chemosynthesis. These producers support large numbers of other organisms, including crustaceans and red tubeworms like those pictured in Figure below .

What is a combination of two or more substances in any proportion called?

solvent

combination

solution

mixture

Not all combined substances are compounds. Some are mixtures. A mixture is a combination of two or more substances in any proportion. The substances in a mixture may be elements or compounds. The substances don’t combine chemically to form a new substance, as they do in a compound. Instead, they keep their original properties and just intermix. Examples of mixtures include salt and water in the ocean and gases in the atmosphere. Other examples are pictured in Figure below .

Where is the youngest seafloor located?

at the floor

at the base

at the reefs

at the ridge

The youngest seafloor is at the ridge. The oldest is farthest from the ridge. The oldest seafloor is much younger than the oldest continent.

What kind of mixture consists of two or more phases, exemplified when a combination of oil and water forms layers?

complex miture

homogeneous

simple mixture

heterogeneous

A phase is any part of a sample that has a uniform composition and properties. By definition, a pure substance or a homogeneous mixture consists of a single phase. A heterogeneous mixture consists of two or more phases. When oil and water are combined, they do not mix evenly, but instead form two separate layers. Each of the layers is called a phase.

The values of strangeness assigned to various particles are based on what?

penetration potential

atomic mass

thermal energy

decay systematics

lifetimes on the order of 10 s (the exception is Σ , whose short lifetime is explained by its particular quark substructure. ), implying that their decay is caused by the weak force alone, although they are hadrons and feel the strong force. The decay modes of these particles also show patterns—in particular, certain decays that should be possible within all the known conservation laws do not occur. Whenever something is possible in physics, it will happen. If something does not happen, it is forbidden by a rule. All this seemed strange to those studying these particles when they were first discovered, so they named a new quantum number strangeness, given the symbol S in the table given above. The values of strangeness assigned to various particles are based on the decay systematics. It is found that strangeness is conserved by the strong force, which.

Together, the muscular and skeletal organs are known as what?

nervous system

lymphatic system

cardiovascular system

musculoskeletal system

CHAPTER REVIEW 6.1 The Functions of the Skeletal System The major functions of the bones are body support, facilitation of movement, protection of internal organs, storage of minerals and fat, and hematopoiesis. Together, the muscular system and skeletal system are known as the musculoskeletal system.

What do factories and power plants use to remove particulates and waste gases from exhaust before releasing it?

catalytic converters

compressors

mufflers

scrubbers

Scrubbers are used in factories and power plants. They remove particulates and waste gases from exhaust before it is released to the air. You can see how a scrubber works in Figure below .

Humans typically have how many pairs of chromosomes?

25 pairs

14 pairs

17 pairs

23 pairs

No, you only received half of your mother's chromosomes and half of your father's chromosomes. If you inherited them all, you would have twice the number of chromosomes that you're supposed to have. Humans typically have 23 pairs of chromosomes. If you received all your parents' chromosomes, you would have 46 pairs!.

Correlation is different from what term that refers to the factor that is producing the effect?

differentiation

manifestation

correlation

causation

But correlation does not necessarily indicate causation. Causation refers to the factor that is producing the effect. If I push a toy car, I will cause it to move. To explain the difference between correlation and causation, let’s look at an example. Sugar consumption in the United States has been rising for decades ( Figure below ). There is a positive correlation between sugar consumption and rising average global temperatures.

What organelles do animal cells use to convert food into energy?

flagellum

endoplasmic reticulum

nucleus

mitochondria

When an animal needs energy, it eats food. That's why animals use mitochondria to convert food into energy. Plants, on the other hand, don't seem to eat anything. Instead, they receive energy from water and sunlight. They use chloroplasts to convert light into energy through photosynthesis. The focus of this concept is to delineate the distinct differences between plant and animal cells.

Where does egg production happen?

testes

uterus

fallopian tube

ovaries

Egg production takes place in the ovaries. It takes several steps to make an egg:.

What can be used to estimate the energy change of a chemical reaction?

isoenergies

bond magnitudes

chemical energy

bond energies

Bond energies can be used to estimate the energy change of a chemical reaction. When bonds are broken in the reactants, the energy change for this process is endothermic. When bonds are formed in the products, the energy change for this process is exothermic. We combine the positive energy change with the negative energy change to estimate the overall energy change of the reaction. For example, in.

Destructive interference occurs when two identical waves are superimposed exactly out of phase. a standing wave is one in which two waves superimpose to produce a wave that varies in amplitude but does not do this?

reproduce

substrate

membrane

propagate

Superposition is the combination of two waves at the same location. Constructive interference occurs when two identical waves are superimposed in phase. Destructive interference occurs when two identical waves are superimposed exactly out of phase. A standing wave is one in which two waves superimpose to produce a wave that varies in amplitude but does not propagate. Nodes are points of no motion in standing waves. An antinode is the location of maximum amplitude of a standing wave. Waves on a string are resonant standing waves with a fundamental frequency and can occur at higher multiples of the fundamental, called overtones or harmonics. Beats occur when waves of similar frequencies f 1 and f 2 are superimposed. The resulting amplitude oscillates with a beat frequency given by.

What is the layer outside the cell wall in a prokaryote?

membrane

rim

pod

capsule

Many prokaryotes have another layer, called a capsule, outside the cell wall. The capsule protects the cell from chemicals and drying out. It also allows the cell to stick to surfaces and to other cells.

What delivers natural gas from rock that might not otherwise be obtainable?

grinding

rippling

drilling

fracking

Fracking delivers natural gas from rock that might not otherwise be obtainable.

Name the white blood cells that can squeeze through capillary walls and swallow particles.

hemoglobin

platelets

lymphocytes

neutrophils

Neutrophils are WBCs that can squeeze through capillary walls and swallow particles such as bacteria and parasites.

Permanent dipole-dipole interactions are found in what kind of molecules?

geologic

directional

dual

polar

Polar molecules have permanent dipole-dipole interactions.

The energy released during an earthquake is called what?

tidal

radiation

hydro

magnitude

The ways seismologists measure an earthquake have changed over the decades. Initially, they could only measure what people felt and saw, the intensity. Now they can measure the energy released during the quake, the magnitude.

Many replication forks develop along a what?

allele

nucleus

genome

chromosome

Many replication forks develop along a chromosome. This process continues until the replication forks meet, and the all of the DNA in a chromosome has been copied. Each new strand that has formed is complementary to the strand used as the template. Each resulting DNA molecule is identical to the original DNA molecule. During prophase of mitosis or prophase I of meiosis, these molecules of DNA condense into a chromosome made of two identical "sister" chromatids. This process ensures that cells that result from cell division have identical sets of genetic material, and that the DNA is an exact copy of the parent cell’s DNA.

What is the term for the strength of an acid or base?

texture

carbon

pH

acidity

The strength of an acid or base is called acidity. It depends on how much of the substance breaks down into ions when it dissolves in water.

A bog is a type of ____

stream

plant

lake

wetland

Not all wetlands are alike, as you can see below ( Figure below ). Wetlands vary in how wet they are and how much of the year they are soaked. Wetlands also vary in the kinds of plants that live in them. This depends mostly on the climate where the wetland is found. Types of wetlands include marshes, swamps, and bogs.

In projectile motion, the horizontal displacement of an object is called its what?

variety

width

height

range

In projectile motion, the horizontal displacement of an object is called its range .

An oil drop is stationary when what downward force exactly equals the upward electrical force on the drop?

radiation

magnetic

newtonian

gravitational

The charge on the plates is adjustable. By measuring the terminal velocity of the oil drops with the electric field off, Millikan could determine the mass of the drops. Millikan and his graduate assistant were able to determine the force of the field on the drops when it was turned on by comparing the velocity of the drops with the field on to their velocity with the field off. This is easily determined when the oil drop is stationary; namely, when the downward gravitational force exactly equals the upward electrical force on the drop.

The secretion of what may influence the body’s circadian rhythms?

serotonin

human growth hormone

testosterone

melatonin

The secretion of melatonin may influence the body’s circadian rhythms, the dark-light fluctuations that affect not only sleepiness and wakefulness, but also appetite and body temperature. Interestingly, children have higher melatonin levels than adults, which may prevent the release of gonadotropins from the anterior pituitary, thereby inhibiting the onset of puberty. Finally, an antioxidant role of melatonin is the subject of current research. Jet lag occurs when a person travels across several time zones and feels sleepy during the day or wakeful at night. Traveling across multiple time zones significantly disturbs the light-dark cycle regulated by melatonin. It can take up to several days for melatonin synthesis to adjust to the light-dark patterns in the new environment, resulting in jet lag. Some air travelers take melatonin supplements to induce sleep.

Photosynthesis takes the energy of sunlight and combines water and carbon dioxide to produce sugar and oxygen as this?

primary product

secondary product

reactive product

waste product

The free electron travels through the electron transport chain, and the energy of the electron is used to pump hydrogen ions into the thylakoid space, transferring the energy into the electrochemical gradient. The energy of the electrochemical gradient is used to power ATP synthase, and the energy is transferred into a bond in the ATP molecule. In addition, energy from another photon can be used to create a high-energy bond in the molecule NADPH. 16 Photosynthesis takes the energy of sunlight and combines water and carbon dioxide to produce sugar and oxygen as a waste product. The reactions of respiration take sugar and consume oxygen to break it down into carbon dioxide and water, releasing energy. Thus, the reactants of photosynthesis are the products of respiration, and vice versa.

Purkinje fibers have a fast inherent what?

induction rate

replication rate

electromagnetic rate

conduction rate

Atrioventricular Bundle (Bundle of His), Bundle Branches, and Purkinje Fibers Arising from the AV node, the atrioventricular bundle, or bundle of His, proceeds through the interventricular septum before dividing into two atrioventricular bundle branches, commonly called the left and right bundle branches. The left bundle branch has two fascicles. The left bundle branch supplies the left ventricle, and the right bundle branch the right ventricle. Since the left ventricle is much larger than the right, the left bundle branch is also considerably larger than the right. Portions of the right bundle branch are found in the moderator band and supply the right papillary muscles. Because of this connection, each papillary muscle receives the impulse at approximately the same time, so they begin to contract simultaneously just prior to the remainder of the myocardial contractile cells of the ventricles. This is believed to allow tension to develop on the chordae tendineae prior to right ventricular contraction. There is no corresponding moderator band on the left. Both bundle branches descend and reach the apex of the heart where they connect with the Purkinje fibers (see Figure 19.19, step 4). This passage takes approximately 25 ms. The Purkinje fibers are additional myocardial conductive fibers that spread the impulse to the myocardial contractile cells in the ventricles. They extend throughout the myocardium from the apex of the heart toward the atrioventricular septum and the base of the heart. The Purkinje fibers have a fast inherent conduction rate, and the electrical impulse reaches all of the ventricular muscle cells in about 75 ms (see Figure 19.19, step 5). Since the electrical stimulus begins at the apex, the contraction also begins at the apex and travels toward the base of the heart, similar to squeezing a tube of toothpaste from the bottom. This allows the blood to be pumped out of the ventricles and into the aorta and pulmonary trunk. The total time elapsed from the initiation of the impulse in the SA node until depolarization of the ventricles is approximately 225 ms.

What process affecting genes or chromosomes causes genetic disorders?

graduation

radiation

infection

mutation

Many genetic disorders are caused by mutations in one or a few genes. Others are caused by chromosomal mutations. Some human genetic disorders are X-linked or Y-linked, which means the faulty gene is carried on these sex chromosomes. Other genetic disorders are carried on one of the other 22 pairs of chromosomes; these chromosomes are known as autosomes or autosomal (non-sex) chromosomes. Some genetic disorders are due to new mutations, others can be inherited from your parents.

What type of engine burns fuel to heat water and produce steam?

conduction

convection

condensation

combustion

An external combustion engine burns fuel to heat water and produce steam. The steam is under pressure and is used to push a piston back and forth inside a cylinder. As the piston moves back and forth, it moves a piston rod, which can do work.

Oncogenesis is one name for the process where normal cells turn into what?

blood cells

lung cells

brain cells

cancer cells

Carcinogenesis is the process by which normal cells are transformed into cancer cells. The process is also known as oncogenesis or tumorigenesis and it depends on both the activation of oncogenes and deactivation of tumor suppressor genes . Proto-oncogenes, the non-cancerous normal version of an oncogene, can be a transcription factor like c-fos, c-jun and c-myc, or a gene whose product is involved in signal transduction, leading to altered gene expression. When mutations cause the regulation of this process to be disturbed, cell proliferation can be enhanced leading to tumorigenesis.

Characteristics of an organism are passed from one generation to the next through what?

eggs

ribosomes

sperm

genes

Characteristics of organisms are passed from one generation to the next through their genes.

Reactants are substances that start what?

consumption reaction

growth reaction

dying reaction

chemical reaction

Reactants are substances that start a chemical reaction.

What are cyclic compounds which have an element other than carbon atoms in the ring?

polymeric compounds

axial compounds

homocyclic compounds

heterocyclic compounds

Note So far we have studied only aromatic compounds with carbon-containing rings. However, many cyclic compounds have an element other than carbon atoms in the ring. These compounds, called heterocyclic compounds, are discussed inChapter 15 "Organic Acids and Bases and Some of Their Derivatives", Section 15.13 "Amines as Bases". Some of these are heterocyclic aromatic compounds. Table 13.4 Some Drugs That Contain a Benzene Ring.

Surviving megaspores develop into what?

singular celled female gametophytes

multicellular male gametophytes

null gametophytes

multicellular female gametophytes

null

Stoichiometry is concerned with the reactants and the products in chemical what?

solvents

photosynthesis

bonds

reactions

numerical relationships between the reactants and the products in balanced chemical reactions is called stoichiometry.

What do you call the angle at which waves strike a wall?

incidence impact

rotation of incidence

angle of impact

angle of incidence

Waves strike a wall at an angle, called the angle of incidence. The waves are reflected at the same angle, called the angle of reflection, but in a different direction. Both angles are measured relative to a line that is perpendicular to the wall.

Nitrogen & sulfur oxide combine with rain to form what?

coarse rain

toxic rain

steam rain

acid rain

Nitrogen and sulfur oxides combine with rain to form acid rain.

The nitrogenous bases found in nucleotides are classified as pyrimidines or what?

Science

Fallen

terpenes

purines

The nitrogenous bases found in nucleotides are classified as pyrimidines or purines. Pyrimidines are heterocyclic amines with two nitrogen atoms in a six-member ring and include uracil, thymine, and cytosine. (For more information about heterocyclic amines, see Chapter 15 "Organic Acids and Bases and Some of Their Derivatives", Section 15.13 "Amines as Bases". ) Purines are heterocyclic amines consisting of a pyrimidine ring fused to a five-member ring with two nitrogen atoms. Adenine and guanine are the major purines found in nucleic acids (Figure 19.2 "The Nitrogenous Bases Found in DNA and RNA"). Figure 19.2 The Nitrogenous Bases Found in DNA and RNA.

Instead of heat, organisms use what to speed up reactions?

synthesis

metabolism

acids

catalysis

null

What term in science describes not just a guess, but a well-formed set of explanations for a phenomenon?

evolution

hypothesis

concept

theory

Some ideas in science gain the status of theories. Scientists use the term "theory" differently than it is used in everyday language. You might say, "I think the dog ate my homework, but it’s just a theory. " In other words, it’s just one of many possible explanations for the missing work. However, in science, a theory is much more than that.

Although helper t cells do not destroy infected or damaged body cells, they are still necessary for what?

lung response

brain response

mutations response

immune response

Helper T cells do not destroy infected or damaged body cells. But they are still necessary for an immune response. They help by releasing chemicals that control other lymphocytes. The chemicals released by helper T cells “switch on” both B cells and killer T cells so they can recognize and fight specific pathogens.

The seven unique crystal types are defined by what parts of themselves (parts that intersect at various angles)?

eyes

shards

angles

faces

Crystals are classified into general categories based on their shapes. A crystal is defined by its faces, which intersect with one another at specific angles, which are characteristic of the given substance. The seven crystal systems are shown below, along with an example of each. The edge lengths of a crystal are represented by the letters , , and . The angles at which the faces intersect are represented by the Greek letters , , and . Each of the seven crystal systems differs in terms of the angles between the faces and in the number of edges of equal length on each face.

In their processes of gene expression, archael cells show similarties to both bacterial cells and which other type of cell?

plant cells

Prokaryotic

chloroplasts

eukaryotic

null

What term refers to the amount of solute that can dissolve in a given amount of solvent at a given temperature?

turbidity

viscosity

saturation

solubility

Solubility is the amount of solute that can dissolve in a given amount of solvent at a given temperature. Some solutes have greater solubility than others.

Although quite different, beryllium, magnesium, calcium, strontium, barium, and radium are all classified as what type of metals?

acidic earth metals

mucous earth metals

detergent earth metals

alkaline earth metals

The Alkaline Earth Metals The alkaline earth metals are beryllium, magnesium, calcium, strontium, barium, and radium. Beryllium, strontium, and barium are rather rare, and radium is unstable and highly radioactive. In contrast, calcium and magnesium are the fifth and sixth most abundant elements on Earth, respectively; they are found in huge deposits of limestone and other minerals.

What predatory mammal is the fastest land animal on earth?

giraffe

panther

tiger

cheetah

Mammals are noted for the many ways they can move about. Generally, their limbs are very mobile. Often, they can be rotated. Many mammals are also known for their speed. The fastest land animal is a predatory mammal. Can you guess what it is? Racing at speeds of up to 112 kilometers (70 miles) per hour, the cheetah wins hands down. In addition, the limbs of mammals let them hold their body up above the ground. That’s because the limbs are attached beneath the body, rather than at the sides as in reptiles (see Figure below ).

Why did woolly mammoths began to go extinct thousands of years ago?

competition for food

volcanic eruptions

parasites

hunting by humans

Woolly mammoths began to go extinct about 10,000 years ago, soon after paleontologists believe humans able to hunt them began to colonize North America and northern Eurasia (Figure 19.8). A mammoth population survived on Wrangel Island, in the East Siberian Sea, and was isolated from human contact until as recently as 1700 BC. We know a lot about these animals from carcasses found frozen in the ice of Siberia and other northern regions. It is commonly thought that climate change and human hunting led to their extinction. A 2008 study estimated that climate change reduced the mammoth’s range from 3,000,000 square miles 42,000 years [3] ago to 310,000 square miles 6,000 years ago. Through archaeological evidence of kill sites, it is also well documented that humans hunted these animals. A 2012 study concluded that no single factor was [4] exclusively responsible for the extinction of these magnificent creatures. In addition to climate change and reduction of habitat, scientists demonstrated another important factor in the mammoth’s extinction was the migration of human hunters across the Bering Strait to North America during the last ice age 20,000 years ago. The maintenance of stable populations was and is very complex, with many interacting factors determining the outcome. It is important to remember that humans are also part of nature. Once we contributed to a species’ decline using primitive hunting technology only.

What is a developing baby called in the very early stages?

sperm

fetus

uterus

embryo

While a woman is pregnant, the developing baby may be called an embryo or a fetus. Do these mean the same thing? No, in the very early stages the developing baby is called an embryo, while in the later stages it is called a fetus. When the ball of cells first implants into the uterus, it is called an embryo . The embryo stage lasts until the end of the 8 th week after fertilization. After that point until birth, the developing baby is called a fetus .

What is released when an atom gains valence electrons and forms a negative ion?

fusion

charge

heat

energy

It takes energy to remove valence electrons from an atom and form a positive ion. Energy is released when an atom gains valence electrons and forms a negative ion.