questions stringlengths 37 1.22k | reasoning stringlengths 0 3.56k ⌀ | answers stringlengths 4 138 |
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In order to conduct what, electrons must move from the filled valence band to the empty conduction band where they can move throughout the solid?
Here are the choices:
A. electricity
B. heat
C. light
D. matter | Figure 8.39 Molecular orbitals in solids are so closely spaced that they are described as bands. The valence band is lower in energy and the conduction band is higher in energy. The type of solid is determined by the size of the “band gap” between the valence and conduction bands. Only a very small amount of energy is required to move electrons from the valance band to the conduction band in a conductor, and so they conduct electricity well. In an insulator, the band gap is large, so that very few electrons move, and they are poor conductors of electricity. Semiconductors are in between: they conduct electricity better than insulators, but not as well as conductors. In order to conduct electricity, electrons must move from the filled valence band to the empty conduction band where they can move throughout the solid. The size of the band gap, or the energy difference between the top of the valence band and the bottom of the conduction band, determines how easy it is to move electrons between the bands. Only a small amount of energy is required in a conductor because the band gap is very small. This small energy difference is “easy” to overcome, so they are good conductors of electricity. In an insulator, the band gap is so “large” that very few electrons move into the conduction band; as a result, insulators are poor conductors of electricity. Semiconductors conduct electricity when “moderate” amounts of energy are provided to move electrons out of the valence band and into the conduction band. Semiconductors, such as silicon, are found in many electronics. Semiconductors are used in devices such as computers, smartphones, and solar cells. Solar cells produce electricity when light provides the energy to move electrons out of the valence band. The electricity that is generated may then be used to power a light or tool, or it can be stored for later use by charging a battery. As of December 2014, up to 46% of the energy in sunlight could be converted into electricity using solar cells. | A: electricity. |
Conductive losses in the middle ear can be partially overcome by sending sound vibrations to what structure through the skull, the principle behind implants for hearing loss patients?
Here are the choices:
A. cochlea
B. hammer and anvil
C. tympanic membrane
D. cornea | Hearing losses can occur because of problems in the middle or inner ear. Conductive losses in the middle ear can be partially overcome by sending sound vibrations to the cochlea through the skull. Hearing aids for this purpose usually press against the bone behind the ear, rather than simply amplifying the sound sent into the ear canal as many hearing aids do. Damage to the nerves in the cochlea is not repairable, but amplification can partially compensate. There is a risk that amplification will produce further damage. Another common failure in the cochlea is damage or loss of the cilia but with nerves remaining functional. Cochlear implants that stimulate the nerves directly are now available and widely accepted. Over 100,000 implants are in use, in about equal numbers of adults and children. The cochlear implant was pioneered in Melbourne, Australia, by Graeme Clark in the 1970s for his deaf father. The implant consists of three external components and two internal components. The external components are a microphone for picking up sound and converting it into an electrical signal, a speech processor to select certain frequencies and a transmitter to transfer the signal to the internal components through electromagnetic induction. The internal components consist of a receiver/transmitter secured in the bone beneath the skin, which converts the signals into electric impulses and sends them through an internal cable. | A: cochlea. |
What is the term for the fast-moving air currents high in the troposphere?
Here are the choices:
A. jet streams
B. ocean streams
C. gale force winds
D. global winds | Jet streams are fast-moving air currents high in the troposphere. They are also the result of unequal heating of the atmosphere. Jet streams circle the planet, mainly from west to east. The strongest jet streams are the polar jets. The northern polar jet is shown in Figure below . | A: jet streams. |
Vibrating electric and magnetic fields make up what kinds of waves?
Here are the choices:
A. electromagnetic
B. mechanical
C. eletrical
D. seismic | What do these two photos have in common? They both represent electromagnetic waves. These are waves that consist of vibrating electric and magnetic fields. They transmit energy through matter or across space. Some electromagnetic waves are generally harmless. The light we use to see is a good example. Other electromagnetic waves can be very harmful and care must be taken to avoid too much exposure to them. X rays are a familiar example. Why do electromagnetic waves vary in these ways? It depends on their properties. Like other waves, electromagnetic waves have properties of speed, wavelength, and frequency. | A: electromagnetic. |
What do you call the regular changes in biology or behavior that occur in a 24-hour cycle?
Here are the choices:
A. variable rhythms
B. circadian rhythms
C. cognitive rhythms
D. sleep rhythms | Circadian rhythms are regular changes in biology or behavior that occur in a 24-hour cycle. In humans, for example, blood pressure and body temperature change in a regular way throughout each 24-hour day. Animals may eat and drink at certain times of day as well. Humans have daily cycles of behavior, too. Most people start to get sleepy after dark and have a hard time sleeping when it is light outside. In many species, including humans, circadian rhythms are controlled by a tiny structure called the biological clock . This structure is located in a gland at the base of the brain. The biological clock sends signals to the body. The signals cause regular changes in behavior and body processes. The amount of light entering the eyes helps control the biological clock. The clock causes changes that repeat every 24 hours. | B: circadian rhythms. |
The electric and magnetic fields are closely related and propagate as what?
Here are the choices:
A. mechanical wave
B. thermal energy
C. electromagnetic wave
D. sound wave | There is an associated magnetic field ( B ) which propagates outward as well (see Figure 24.6). The electric and magnetic fields are closely related and propagate as an electromagnetic wave. This is what happens in broadcast antennae such as those in radio and TV stations. Closer examination of the one complete cycle shown in Figure 24.5 reveals the periodic nature of the generator-driven charges oscillating up and down in the antenna and the electric field produced. At time t = 0 , there is the maximum separation of charge, with negative charges at the top and positive charges at the bottom, producing the maximum magnitude of the electric field (or E -field) in the upward direction. One-fourth of a cycle later, there is no charge separation and the field next to the antenna is zero, while the maximum. | C: electromagnetic wave. |
What do you get by multiplying volume by the density of water?
Here are the choices:
A. weight of water
B. mass of water
C. velocity of water
D. temperature of water | Consider a gigantic tub filled with water as shown below. A column of water with a cross-sectional area of 1.00 m 2 is designated. If we multiply the cross-sectional area by the height of the column, we get the volume of water in this column. We can then multiply this volume by the density of water, 1000. kg/m 3 , and get the mass of water in the column. We then multiply this mass by the acceleration due to gravity, , to get the weight of the water in this column. | B: mass of water. |
Plant-like protists are autotrophs capable of what process?
Here are the choices:
A. photosynthesis
B. microevolution
C. sexual reproduction
D. regeneration | Plant-like protists, which are autotrophs that photosynthesize. | A: photosynthesis. |
What type of energy is useful to humans because it's ease of transport and conversion to other forms of energy?
Here are the choices:
A. electrical
B. potential
C. heat
D. physical | Electrical energy is useful to us mostly because it is easy to transport and can be easily converted to or from other forms of energy. Of course, conversion involves wast, typically as heat. | A: electrical. |
When performing anaerobic exercise, your muscles work against what?
Here are the choices:
A. inertia
B. gravity
C. resistance
D. momentum | Anaerobic exercises involve the muscles working against resistance. In this case the resistance is the weight of a barbell. | C: resistance. |
What type of doctor specializes in the laboratory detection of disease?
Here are the choices:
A. infectious disease physician
B. internist
C. pathologist
D. diagnostician | Pathologist A pathologist is a medical doctor or veterinarian who has specialized in the laboratory detection of disease in animals, including humans. These professionals complete medical school education and follow it with an extensive post-graduate residency at a medical center. A pathologist may oversee clinical laboratories for the evaluation of body tissue and blood samples for the detection of disease or infection. They examine tissue specimens through a microscope to identify cancers and other diseases. Some pathologists perform autopsies to determine the cause of death and the progression of disease. | C: pathologist. |
The smallest unit of structure and function in all living organisms is what?
Here are the choices:
A. particle
B. cell
C. compound
D. mineral | The cell is the smallest unit of structure and function of all living organisms. Cell Biology focuses on significant aspects of the cell from its structure to its division. Some organisms contain just one cell, and others contain trillions. Some have a nucleus with DNA, others do not. Some have many organelles, others do not. But all cells are surrounded by a cell membrane. And it is this semipermeable membrane that determines what can enter and leave the cell. All cells need energy, and for many organisms, this energy comes from photosynthesis and cellular respiration. All cells come from preexisting cells through the process of cell division, which can produce a new prokaryotic organism. The cell cycle, which includes mitosis, defines the life of an eukaryotic cell. | B: cell. |
Bilaterally symmetrical animals have both dorsal and what type of sides?
Here are the choices:
A. posterior
B. anterior
C. ventral
D. exterior | C: ventral. | |
Which state of matter is not common on earth?
Here are the choices:
A. plasma
B. liquid
C. respiration
D. gas | States of matter are different phases in which any given type of matter can exist. There are four well-known states of matter—solid, liquid, gas, and plasma—but only the first three states are common on Earth. | A: plasma. |
Which system of the body is responsible for bringing air into the body?
Here are the choices:
A. vascular system
B. digestive system
C. excretory system
D. respiratory system | We breathe because we need oxygen. Breathing also releases carbon dioxide from our bodies into the air. The respiratory system is the body system that brings air containing oxygen into the body and releases carbon dioxide into the atmosphere. Recall that oxygen is needed to make ATP. | D: respiratory system. |
The photoreceptive cells of the eye, where transduction of light to nervous impulses occurs, are located in this?
Here are the choices:
A. retina
B. sclera
C. cornea
D. pupil | Anatomy of the Eye The photoreceptive cells of the eye, where transduction of light to nervous impulses occurs, are located in the retina (shown in Figure 36.17) on the inner surface of the back of the eye. But light does not impinge on the retina unaltered. It passes through other layers that process it so that it can be interpreted by the retina (Figure 36.17b). The cornea, the front transparent layer of the eye, and the crystalline lens, a transparent convex structure behind the cornea, both refract (bend) light to focus the image on the retina. The iris, which is conspicuous as the colored part of the eye, is a circular muscular ring lying between the lens and cornea that regulates the amount of light entering the eye. In conditions of high ambient light, the iris contracts, reducing the size of the pupil at its center. In conditions of low light, the iris relaxes and the pupil enlarges. | A: retina. |
E. coli need what kind of acids to survive?
Here are the choices:
A. bacterial
B. hydrochloric
C. amino
D. boric | The trp Operon: A Repressor Operon Bacteria such as E. coli need amino acids to survive. Tryptophan is one such amino acid that E. coli can ingest from the environment. coli can also synthesize tryptophan using enzymes that are encoded by five genes. These five genes are next to each other in what is called the tryptophan (trp) operon (Figure 16.3). If tryptophan is present in the environment, then E. coli does not need to synthesize it and the switch controlling the activation of the genes in the trp operon is switched off. However, when tryptophan availability is low, the switch controlling the operon is turned on, transcription is initiated, the genes are expressed, and tryptophan is synthesized. | C: amino. |
Elements are defined by their atomic number, a number that describes the amount of what in the element?
Here are the choices:
A. neutrons
B. bonds
C. protons
D. electrons | Rutherford’s nuclear model of the atom helped explain why atoms of different elements exhibit different chemical behavior. The identity of an element is defined by itsatomic number (Z), the number of protons in the nucleus of an atom of the element. The atomic number is therefore different for each element. The known elements are arranged in order of increasing Z in the periodic table (Figure 1.24 "The Periodic Table Showing the Elements in Order of Increasing "; also see Chapter 32 "Appendix H: Periodic Table of Elements"),. | C: protons. |
What laboratory instrument is used to analyze and test for static charge?
Here are the choices:
A. microtome
B. microscope
C. bunsen burner
D. electroscope | A laboratory instrument used to analyze and test for static charge is called an electroscope. Seen below, an electroscope consists of a metal knob connected by a metal stem to two very lightweight pieces of metal called leaves, shown in yellow. The leaves are enclosed in a box to eliminate stray air currents. | D: electroscope. |
Through a succession of mitotic cell divisions, what gives rise to a large number of cells?
Here are the choices:
A. air
B. cytoplasm
C. condensation
D. zygote | D: zygote. | |
Contour tillage helps slow water run-off and what process that causes topsoil loss?
Here are the choices:
A. water erosion
B. plate tectonics
C. soil erosion
D. ice shelf erosion | C: soil erosion. | |
In a scientific experiment, the variable that is affected by the other one is called what?
Here are the choices:
A. essential variable
B. independent variable
C. dependent variable
D. effective variable | An experiment generally tests how one variable is affected by another. The affected variable is called the dependent variable . In the plant experiment shown in the Figure above , the dependent variable is plant growth. The variable that affects the dependent variable is called the independent variable . In the plant experiment, the independent variable is fertilizer—some plants will get fertilizer, others will not. In any experiment, other factors that might affect the dependent variable must be controlled. In the plant experiment, what factors do you think should be controlled? ( Hint: What other factors might affect plant growth?). | C: dependent variable. |
Cells must also be able to separate their relatively stable interior from what?
Here are the choices:
A. predators
B. the external environment
C. their habitat
D. competition and chaos | Cells share the same needs: the need to get energy from their environment, the need to respond to their environment, and the need to reproduce. Cells must also be able to separate their relatively stable interior from the ever-changing external environment. They do this by coordinating many processes that are carried out within organelles, or other cellular structures. Structures that are common to many different cells indicate the common history shared by cell-based life. Examples of these common structures include the components of both the cell (or plasma) membrane and the cytoskeleton, and other structures shown in Figure above . | B: the external environment. |
For any given species, what term means the maximum population that can be supported by the environment?
Here are the choices:
A. zero population growth
B. carrying capacity
C. tipping point
D. mass extinction | A population can’t keep growing bigger and bigger forever. Sooner or later, it will run out of things it needs. For a given species, there is a maximum population that can be supported by the environment. This maximum is called the carrying capacity . When a population gets close to the carrying capacity, it usually grows more slowly ( Figure below ). When the population reaches the carrying capacity, it stops growing. | B: carrying capacity. |
With an increased understanding of gene regulation and gene function, medicines can be designed to specifically target diseased cells without harming these?
Here are the choices:
A. hosts
B. stem cells
C. healthy cells
D. pathogens | New Drugs to Combat Cancer: Targeted Therapies Scientists are using what is known about the regulation of gene expression in disease states, including cancer, to develop new ways to treat and prevent disease development. Many scientists are designing drugs on the basis of the gene expression patterns within individual tumors. This idea, that therapy and medicines can be tailored to an individual, has given rise to the field of personalized medicine. With an increased understanding of gene regulation and gene function, medicines can be designed to specifically target diseased cells without harming healthy cells. Some new medicines, called targeted therapies, have exploited the overexpression of a specific protein or the mutation of a gene to develop a new medication to treat disease. One such example is the use of anti-EGF receptor medications to treat the subset of breast cancer tumors that have very high levels of the EGF protein. Undoubtedly, more targeted therapies will be developed as scientists learn more about how gene expression changes can cause cancer. | C: healthy cells. |
The rate of a reaction can be expressed either in terms of the decrease in the amount of what or the increase in the amount of a product per unit time?
Here are the choices:
A. sulfate
B. plasma
C. isotope
D. reactant | Summary 12.1 Chemical Reaction Rates The rate of a reaction can be expressed either in terms of the decrease in the amount of a reactant or the increase in the amount of a product per unit time. Relations between different rate expressions for a given reaction are derived directly from the stoichiometric coefficients of the equation representing the reaction. 12.2 Factors Affecting Reaction Rates The rate of a chemical reaction is affected by several parameters. Reactions involving two phases proceed more rapidly when there is greater surface area contact. If temperature or reactant concentration is increased, the rate of a given reaction generally increases as well. A catalyst can increase the rate of a reaction by providing an alternative pathway that causes the activation energy of the reaction to decrease. 12.3 Rate Laws Rate laws provide a mathematical description of how changes in the amount of a substance affect the rate of a chemical reaction. Rate laws are determined experimentally and cannot be predicted by reaction stoichiometry. The order of reaction describes how much a change in the amount of each substance affects the overall rate, and the overall order of a reaction is the sum of the orders for each substance present in the reaction. Reaction orders are typically first order, second order, or zero order, but fractional and even negative orders are possible. 12.4 Integrated Rate Laws Differential rate laws can be determined by the method of initial rates or other methods. We measure values for the initial rates of a reaction at different concentrations of the reactants. From these measurements, we determine the order of the reaction in each reactant. Integrated rate laws are determined by integration of the corresponding differential. | D: reactant. |
What do molecules need to do for a reaction to take place?
Here are the choices:
A. melt
B. explode
C. separate
D. collide | Molecules need to collide in order for a reaction to take place. | D: collide. |
What is the term for the change in temperature with distance?
Here are the choices:
A. distance gradient
B. heat gradient
C. temperature volatility
D. temperature gradient | Temperature gradient is the change in temperature with distance. | D: temperature gradient. |
How many classes of biochemical compounds are there?
Here are the choices:
A. three
B. four
C. five
D. one | Hemoglobin is a compound in the class of compounds called proteins. Proteins are one of four classes of biochemical compounds, which are compounds in living things. (The other three classes are carbohydrates, lipids, and nucleic acids. ) Proteins contain carbon, hydrogen, oxygen, nitrogen, and sulfur. Protein molecules consist of one or more chains of small molecules called amino acids. | B: four. |
The fact that all animals have certain traits in common shows that they share what?
Here are the choices:
A. a common gene
B. a common brain
C. a common planet
D. a common ancestor | There is great variation among species that make up the animal kingdom. Some of this variation is shown in Figure below . Despite the variation, there are a number of traits that are shared by all animals. The fact that all animals have certain traits in common shows that they share a common ancestor. How did such a diverse group of organisms evolve? What traits do all animals share? Read on to find out. | D: a common ancestor. |
Organisms that live in freshwater environments often possess a contractile vacuole that prevents cells from taking in too much water through what process?
Here are the choices:
A. electrolysis
B. hemostasis
C. glycolysis
D. osmosis | Organisms that live in a hypotonic environment such as freshwater, need a way to prevent their cells from taking in too much water by osmosis. A contractile vacuole is a type of vacuole that removes excess water from a cell. Freshwater protists, such as the paramecia shown in Figure below , have a contractile vacuole. The vacuole is surrounded by several canals, which absorb water by osmosis from the cytoplasm. After the canals fill with water, the water is pumped into the vacuole. When the vacuole is full, it pushes the water out of the cell through a pore. Other protists, such as members of the genus Amoeba , have contractile vacuoles that move to the surface of the cell when full and release the water into the environment. | D: osmosis. |
What is the condition in which the thyroid gland is overactive is known as?
Here are the choices:
A. susceptibility
B. hyperthyroidism
C. hypothyroidism
D. hepatic | Hyperthyroidism is a condition in which the thyroid gland is overactive. Hypothyroidism is a condition in which the thyroid gland is underactive. Which of the conditions are the following two patients most likely to have? Patient A has symptoms including weight gain, cold sensitivity, low heart rate and fatigue. Patient B has symptoms including weight loss, profuse sweating, increased heart rate and difficulty sleeping. | B: hyperthyroidism. |
Where do amphibians lay their eggs?
Here are the choices:
A. in caves
B. on land
C. in water
D. in airborne nests | Amphibians reproduce sexually. Fertilization may take place inside or outside the body. Eggs are laid in water. They hatch into larvae that live in the water until they undergo metamorphosis to the adult form. | C: in water. |
The food particles are caught by the collar of the choanocyte and brought into the cell by what process?
Here are the choices:
A. phototropism
B. cellular respiration
C. hippocampus
D. phagocytosis | Chapter 15 1 Figure 15.3 B 3 Figure 15.33 A 4 B 6 D 8 B 10 A 12 B 14 C 16 C 18 A 20 Specialized tissues allow more efficient functioning because differentiated tissue types can perform unique functions and work together in tandem to allow the animal to perform more functions. For example, specialized muscle tissue allows directed and efficient movement, and specialized nervous tissue allows for multiple sensory modalities as well as the ability to respond to various sensory information; these functions are not necessarily available to other non-animal organisms. 22 The sponges draw water carrying food particles into the spongocoel using the beating of flagella in the choanocytes. The food particles are caught by the collar of the choanocyte and brought into the cell by phagocytosis. Digestion of the food particle takes place inside the cell. The difference between this and the mechanisms of other animals is that digestion takes place within cells rather than outside of cells. It means that the organism can feed only on particles smaller than the cells themselves. 24 In a complete digestive system, food material is not mixed with waste material, so the digestion and uptake of nutrients can be more efficient. In addition, the complete digestive system allows for an orderly progression of digestion of food matter and the specialization of different zones of the digestive tract. 26 Mollusks have a large muscular foot that may be modified in various ways, such as into tentacles, but it functions in locomotion. They have a mantle, a structure of tissue that covers and encloses the dorsal portion of the animal and secretes the shell when it is present. The mantle encloses the mantle cavity, which houses the gills (when present), excretory pores, anus, and gonadopores. The coelom of mollusks is restricted to the region around the systemic heart. The main body cavity is a hemocoel. Many mollusks have a radula near the mouth that is used for scraping food. 28 During embryonic development, we also have a notochord, a dorsal hollow nerve tube, pharyngeal slits, and a post-anal tail. 30 A moist environment is required as frog eggs lack a shell and dehydrate quickly in dry environments. | D: phagocytosis. |
In seedless vascular plants such as ferns, the sporophyte releases spores from the undersides of what basic plant structures?
Here are the choices:
A. fruits
B. roots
C. stems
D. leaves | In seedless vascular plants such as ferns, the sporophyte releases spores from the undersides of leaves. | D: leaves. |
There are two basic body plans in cnidarians which are called the polyp and what else?
Here are the choices:
A. spore
B. hydra
C. stoma
D. medusa | There are two basic body plans in cnidarians. They are called the polyp and medusa. Both are shown in Figure below . The polyp has a tubular body and is usually sessile. The medusa (plural, medusae ) has a bell-shaped body and is typically motile. Some cnidarian species alternate between polyp and medusa forms. Other species exist in just one form or the other. | D: medusa. |
In science, what is a bit of information that is true?
Here are the choices:
A. theory
B. falsehood
C. lie
D. a fact | Scientists usually begin an investigation with facts. A fact is a bit of information that is true. Facts come from data collected from observations. Facts can also come from experiments that have been run. Data is factual information that results from an investigation. Facts and data are not subject to opinion or bias. An opinion is someone's subjective view or position on a subject. | D: a fact. |
What kind of potentially harmful compounds can barbecuing food create?
Here are the choices:
A. mutagens
B. triglycerides
C. carcinogens
D. enzymes | Barbecued foods are cooked at very high temperatures. This may cause carcinogens to form. | C: carcinogens. |
Change in what equals the average net external force multiplied by the time this force acts?
Here are the choices:
A. lag
B. momentum
C. rate
D. height | Δp = F netΔt, we can see how the change in momentum equals the average net external force multiplied by the time this force acts. The quantity F net Δt is given the name impulse. Impulse is the same as the change in momentum. Impulse: Change in Momentum Change in momentum equals the average net external force multiplied by the time this force acts. | B: momentum. |
What type of mammals are characterized by detailed development of the hands and feet, a shortened snout, and a large brain?
Here are the choices:
A. amphibians
B. primates
C. mammles
D. apes | Primates include monkeys, apes and humans. These mammals are characterized by detailed development of the hands and feet, a shortened snout, and a large brain. | B: primates. |
What process allows an individual to develop from a single cell into an organism with trillions of cells?
Here are the choices:
A. Cell multiplication
B. cell transition
C. cell function
D. cell division | You consist of a great many cells, but like all other organisms, you started life as a single cell. How did you develop from a single cell into an organism with trillions of cells? The answer is cell division. After cells grow to their maximum size, they divide into two new cells. These new cells are small at first, but they grow quickly and eventually divide and produce more new cells. This process keeps repeating in a continuous cycle. | D: cell division. |
What do you call the membrane-bounded droplets that have some properties of cells?
Here are the choices:
A. sporozoans
B. protocells
C. rods
D. membranes. | B: protocells. | |
Bees are naturalized on every continent except which?
Here are the choices:
A. Australia
B. antarctica
C. North America
D. Africa | Honeybees are one of the most well-known insects on the planet. Bees are naturalized on every continent except Antarctica. Honeybees have a highly developed social structure and depend on their community, or colony, for survival, with a colony containing up to 20,000 bees. When bees search plants for nectar, pollen sticks to the fuzzy hairs that cover their hind legs. At the next flower, some of the pollen rubs off and fertilizes that flower. In this way, bees help improve fruit production. Bees pollinate an estimated 130 different varieties of fruit, flowers, nuts and vegetables in the United States alone. Farmers obviously depend on bees to pollinate crops, such as fruit and nuts, but in recent years thousands of bee colonies have disappeared. This could be a devastating issue for farmers. Can anything be done? Meet two Northern California researchers looking for ways to make sure we always have bees to pollinate crops at http://www. kqed. org/quest/television/better-bees-super-bee-and-wild-bee . | B: antarctica. |
In arthropods, coxal glands and malphigian tubules perform what role?
Here are the choices:
A. ingestion
B. reproduction
C. excretion
D. photosynthesis | Some arthropods have special excretory structures. They are called coxal glands and Malphigian tubules. Coxal glands collect and concentrate liquid waste from blood. They excrete the waste from the body through a pore. Malphigian tubules carry waste from the digestive tract to the anus. The waste is excreted through the anus. | C: excretion. |
What is the ultimate source of energy for all life on earth?
Here are the choices:
A. Mars
B. the moon
C. its core
D. the sun | D: the sun. | |
What do you call compounds whose properties are different because their atoms are bonded together in different arrangements?
Here are the choices:
A. mixtures
B. ionic compounds
C. isotopes
D. isomers | Hydrocarbons are compounds that contain only carbon and hydrogen atoms. The smallest hydrocarbon, methane (CH 4 ), contains just one carbon atom and four hydrogen atoms. Larger hydrocarbons contain many more. Hydrocarbons with four or more carbon atoms can have different shapes. Although they have the same chemical formula, with the same numbers of carbon and hydrogen atoms, they form different compounds, called isomers . Isomers are compounds whose properties are different because their atoms are bonded together in different arrangements. | D: isomers. |
What celestial object has been visited by manned spacecraft and is easily seen from earth?
Here are the choices:
A. venus
B. Jupiter
C. the Sun
D. moon | The Moon is easily seen from Earth. Early astronomers used telescopes to study and map its surface. The Moon has also seen a great number of satellites, rovers, and orbiters. After all, it is relatively easy to get spacecraft to the satellite. Also, before humans could be safely sent to the Moon, many studies and experiments had to be completed. | D: moon. |
What do you call a condition caused by mutations in one or more genes?
Here are the choices:
A. evolutionary disorder
B. mutation disorder
C. intrinsic disorder
D. genetic disorder | Mutations can result in errors in protein sequence, creating partially or completely non-functional proteins. These can obviously result in harm to the cell and organism. To function correctly and maintain homeostasis , each cell depends on thousands of proteins to all work together to perform the functions of the cell. When a mutation alters a protein that plays a critical role in the cell, the cell, tissue, organ, or organ system may not function properly, resulting in a medical condition. A condition caused by mutations in one or more genes is called a genetic disorder or genetic disease. However, only a small percentage of mutations cause genetic disorders; most have no impact on health. If a mutation does not change the protein sequence or structure, resulting in the same function, it will have no effect on the cell. Often, these mutations are repaired by the DNA repair system of the cell. Each cell has a number of pathways through which enzymes recognize and repair mistakes in DNA ( Figure below ). Because DNA can be damaged or mutated in many ways, the process of DNA repair is an important way in which the cell protects itself to maintain proper function. | D: genetic disorder. |
What is the common term for erythrocytesare, specialized cells that circulate delivering oxygen to cells and are formed from stem cells in the bone marrow?
Here are the choices:
A. white blood cells
B. red blood cells
C. plateletes
D. monocytes | Red Blood Cells Red blood cells, or erythrocytes (erythro- = “red”; -cyte = “cell”), are specialized cells that circulate through the body delivering oxygen to cells; they are formed from stem cells in the bone marrow. In mammals, red blood cells are small biconcave cells that at maturity do not contain a nucleus or mitochondria and are only 7–8 µm in size. In birds and nonavian reptiles, a nucleus is still maintained in red blood cells. The red coloring of blood comes from the iron-containing protein hemoglobin, illustrated in Figure 40.6a. The principal job of this protein is to carry oxygen, but it also transports carbon dioxide as well. Hemoglobin is packed into red blood cells at a rate of about 250 million molecules of hemoglobin per cell. Each hemoglobin molecule binds four oxygen molecules so that each red blood cell carries one billion molecules of oxygen. There are approximately 25 trillion red blood cells in the five liters of blood in the human body, which could carry up to 25 sextillion (25 × 1021) molecules of oxygen in the body at any time. In mammals, the lack of organelles in erythrocytes leaves more room for the hemoglobin molecules, and the lack of mitochondria also prevents use of the oxygen for metabolic respiration. Only mammals have anucleated red blood cells, and some mammals (camels, for instance) even have nucleated red blood cells. The advantage of nucleated red blood cells is that these cells can undergo mitosis. Anucleated red blood cells metabolize anaerobically (without oxygen), making use of a primitive metabolic pathway to produce ATP and increase the efficiency of oxygen transport. Not all organisms use hemoglobin as the method of oxygen transport. Invertebrates that utilize hemolymph rather than blood use different pigments to bind to the oxygen. These pigments use copper or iron to the oxygen. Invertebrates have a variety of other respiratory pigments. Hemocyanin, a blue-green, copper-containing protein, illustrated in Figure 40.6b is found in mollusks, crustaceans, and some of the arthropods. Chlorocruorin, a green-colored, iron-containing pigment is found in four families of polychaete tubeworms. Hemerythrin, a red, iron-containing protein is found in some polychaete worms and annelids and is illustrated in Figure 40.6c. Despite the name, hemerythrin does not contain a heme group and its oxygen-carrying capacity is poor compared to hemoglobin. | B: red blood cells. |
When do glaciers deposit their sediment?
Here are the choices:
A. when they form
B. when they are new
C. when they melt
D. when they move | Glaciers deposit their sediment when they melt. Landforms deposited by glaciers include drumlins, kettle lakes, and eskers. | C: when they melt. |
One of the earliest air pumps was made by?
Here are the choices:
A. Galileo
B. robert boyle
C. Niels Bohr
D. Isaac Newton | One of the earliest air pumps was made by Robert Boyle. The figure below is a diagram of his early pump. | B: robert boyle. |
Terrestrial biomes are determined mainly by what?
Here are the choices:
A. landscape
B. climate
C. population
D. element | Terrestrial biomes are determined mainly by climate. | B: climate. |
What are scientists able to determine about stars using emission and absorption spectra?
Here are the choices:
A. size
B. distance
C. shape
D. composition | Absorption of light by a hydrogen atom. (a) When a hydrogen atom absorbs a photon of light, an electron is excited to an orbit that has a higher energy and larger value of n. (b) Images of the emission and absorption spectra of hydrogen are shown here. Emission and absorption spectra form the basis of spectroscopy, which uses spectra to provide information about the structure and the composition of a substance or an object. In particular, astronomers use emission and absorption spectra to determine the composition of stars and interstellar matter. As an example, consider the spectrum of sunlight shown in Figure 6.14 "The Visible Spectrum of Sunlight". Because the sun is very hot, the light it emits is in. | D: composition. |
Scientists search for answers to questions and solutions to problems by using a procedure called this?
Here are the choices:
A. measured method
B. continued method
C. scientific method
D. careful method | Scientists search for answers to questions and solutions to problems by using a procedure called the scientific method. This procedure consists of makingobservations, formulating hypotheses, and designing experiments, which in turn lead to additional observations, hypotheses, and experiments in repeated cycles (Figure 1.4 "The Scientific Method"). | C: scientific method. |
What transmits nerve impulses to other cells?
Here are the choices:
A. fats
B. muscles
C. ions
D. neurons | Neurons transmit nerve impulses to other cells. | D: neurons. |
The active transport of ions across the membrane causes an electrical gradient to build up across the what?
Here are the choices:
A. cells membrane
B. colloidal membrane
C. components membrane
D. plasma membrane | The active transport of ions across the membrane causes an electrical gradient to build up across the plasma membrane. The number of positively charged ions outside the cell is greater than the number of positively charged ions in the cytosol. This results in a relatively negative charge on the inside of the membrane, and a positive charge on the outside. This difference in charges causes a voltage across the membrane. Voltage is electrical potential energy that is caused by a separation of opposite charges, in this case across the membrane. The voltage across a membrane is called membrane potential . Membrane potential is very important for the conduction of electrical impulses along nerve cells. | D: plasma membrane. |
What process determines which of two fossils is older or younger than the other?
Here are the choices:
A. differential dating
B. relative dating
C. difference dating
D. curve dating | Relative dating determines which of two fossils is older or younger than the other, but not their age in years. Relative dating is based on the positions of fossils in rock layers. Lower layers were laid down earlier, so they are assumed to contain older fossils. This is illustrated in Figure below . | B: relative dating. |
Under which process do living things with beneficial traits produce more offspring?
Here are the choices:
A. evolution
B. migration
C. differentiation
D. natural selection | The other idea is that evolution occurs by natural selection. Natural selection is the process in which living things with beneficial traits produce more offspring. As a result, their traits increase in the population over time. | D: natural selection. |
Biceps brachii, brachialis, and brachioradialis work to flex what part of the body?
Here are the choices:
A. forearm
B. foot
C. leg
D. lungs | extensors are the triceps brachii and anconeus. The pronators are the pronator teres and the pronator quadratus, and the supinator is the only one that turns the forearm anteriorly. When the forearm faces anteriorly, it is supinated. When the forearm faces posteriorly, it is pronated. The biceps brachii, brachialis, and brachioradialis flex the forearm. The two-headed biceps brachii crosses the shoulder and elbow joints to flex the forearm, also taking part in supinating the forearm at the radioulnar joints and flexing the arm at the shoulder joint. Deep to the biceps brachii, the brachialis provides additional power in flexing the forearm. Finally, the brachioradialis can flex the forearm quickly or help lift a load slowly. These muscles and their associated blood vessels and nerves form the anterior compartment of the arm (anterior flexor compartment of the arm) (Figure 11.25 and Figure 11.26). | A: forearm. |
Cancer involves what changes that modify cell-cycle control and alter the growth rate or progression of the cell through the cell cycle?
Here are the choices:
A. deletions
B. enhancements
C. stabilization
D. mutations | 16.7 | Cancer and Gene Regulation By the end of this section, you will be able to: • Describe how changes to gene expression can cause cancer • Explain how changes to gene expression at different levels can disrupt the cell cycle • Discuss how understanding regulation of gene expression can lead to better drug design Cancer is not a single disease but includes many different diseases. In cancer cells, mutations modify cell-cycle control and cells don’t stop growing as they normally would. Mutations can also alter the growth rate or the progression of the cell through the cell cycle. One example of a gene modification that alters the growth rate is increased phosphorylation of cyclin B, a protein that controls the progression of a cell through the cell cycle and serves as a cell-cycle checkpoint protein. For cells to move through each phase of the cell cycle, the cell must pass through checkpoints. This ensures that the cell has properly completed the step and has not encountered any mutation that will alter its function. Many proteins, including cyclin B, control these checkpoints. The phosphorylation of cyclin B, a post-translational event, alters its function. As a result, cells can progress through the cell cycle unimpeded, even if mutations exist in the cell and its growth should be terminated. This post-translational change of cyclin B prevents it from controlling the cell cycle and contributes to the development of cancer. | D: mutations. |
Glucose, fructose, and galactose are hexose sugars, which contain six atoms of what element?
Here are the choices:
A. carbon
B. oxygen
C. nitrogen
D. hydrogen | Monosaccharides A monosaccharide is a monomer of carbohydrates. Five monosaccharides are important in the body. Three of these are the hexose sugars, so called because they each contain six atoms of carbon. These are glucose, fructose, and galactose, shown in Figure 2.18a. The remaining monosaccharides are the two pentose sugars, each of which contains five atoms of carbon. They are ribose and deoxyribose, shown in Figure 2.18b. | A: carbon. |
When an action and reaction occur, what is transferred from one object to the other, yet in combination it remains the same?
Here are the choices:
A. momentum
B. force
C. matter
D. energy | When an action and reaction occur, momentum is transferred from one object to the other. However, the combined momentum of the objects remains the same. In other words, momentum is conserved. This is the law of conservation of momentum . | A: momentum. |
Which two planetary bodies have humans walked on?
Here are the choices:
A. earth and the moon
B. The Sun and Mars
C. Mars and Jupiter
D. Earth and Saturn | Humans have walked on only two planetary bodies: Earth and the Moon. The footprints the men left behind are the first signs of life ever on the Moon. Scientists learned a great deal about the Moon from the Apollo missions. The samples that were brought back have been studied in laboratories. We know an incredible amount about the Moon because of these samples. Having these rocks radically changed our thinking about the Moon. | A: earth and the moon. |
The pion can only be created by violating the conservation of what?
Here are the choices:
A. momentum
B. quantum physics
C. mass-energy
D. time-space | Specifically for the strong nuclear force, Yukawa proposed that a previously unknown particle, now called a pion, is exchanged between nucleons, transmitting the force between them. Figure 33.3 illustrates how a pion would carry a force between a proton and a neutron. The pion has mass and can only be created by violating the conservation of mass-energy. This is allowed by the Heisenberg uncertainty principle if it occurs for a sufficiently short period of time. As discussed in Probability: The Heisenberg Uncertainty Principle the Heisenberg uncertainty principle relates the uncertainties ΔE in energy and Δt in time by. | C: mass-energy. |
What are named for their “spiny skin”?
Here are the choices:
A. arachnids
B. echinoderms
C. amphibians
D. reptiles | Echinoderms are named for their “spiny skin. ” However, the spines aren’t on their skin. They are part of the endoskeleton. The endoskeleton consists of calcium carbonate plates and spines, covered by a thin layer of skin. Adult echinoderms have radial symmetry . This is easy to see in the sea star and sand dollar in Figure above . However, echinoderms evolved from an ancestor with bilateral symmetry. Evidence for this is the bilateral symmetry of their larvae. | B: echinoderms. |
What is formed when sperm mixes with secretions from the various other glands of the reproductive system?
Here are the choices:
A. urine
B. semen
C. testosterone
D. hormone | Sperm leave the epididymis through the vas deferens. As they travel through the vas deferens, they pass by the prostate and other glands. The sperm mix with secretions from these glands, forming semen. Semen travels through the urethra and leaves the body through the penis. A teaspoon of semen may contain as many as half a billion sperm!. | B: semen. |
Some plants have stolons, or stems, that run along the ground and are commonly called what?
Here are the choices:
A. shoots
B. roots
C. stages
D. runners | Figure 32.25 A stolon, or runner, is a stem that runs along the ground. At the nodes, it forms adventitious roots and buds that grow into a new plant. | D: runners. |
Clearing land for agriculture and development is a major cause of what negative result?
Here are the choices:
A. habitat destruction
B. mineral destruction
C. water destruction
D. human destruction | Clearing land for agriculture and development is a major cause of habitat destruction. Within the past 100 years, the amount of total land used for agriculture has almost doubled. Land used for grazing cattle has more than doubled. Agriculture alone has cost the United States half of its wetlands ( Figure below ) and almost all of its tallgrass prairies. Native prairie ecosystems, with their thick fertile soils, deep-rooted grasses, diversity of colorful flowers, burrowing prairie dogs, and herds of bison and other animals, have virtually disappeared ( Figure below ). | A: habitat destruction. |
What in the skin dilates, or widens, in order to increase blood flow to the bodys surface?
Here are the choices:
A. blood vessels
B. veins
C. tear ducts
D. pores | The skin helps maintain a constant body temperature. It keeps the body cool in two ways. Sweat from sweat glands in the skin evaporates to cool the body. Blood vessels in the skin dilate, or widen, increasing blood flow to the body surface. This allows more heat to reach the surface and radiate into the environment. The opposite happens to retain body heat. Blood vessels in the skin constrict, or narrow, decreasing blood flow to the body surface. This reduces the amount of heat that reaches the surface so less heat is lost to the environment. | A: blood vessels. |
What burns to produce the white light in fireworks displays?
Here are the choices:
A. nitrogen in air
B. oxygen in air
C. helium in air
D. magnesium in air | The white light in fireworks displays is produced by burning magnesium in air, which contains oxygen. What compound is formed?. | D: magnesium in air. |
Solids can be divided into amorphous solids and which other group?
Here are the choices:
A. morphous solids
B. crystalline solids
C. acrystalline solids
D. distinct solids | Solids can be divided into amorphous solids and crystalline solids. | B: crystalline solids. |
Some earthworms can also reproduce asexually by fragmentation followed by what?
Here are the choices:
A. germination
B. fertilization
C. digestion
D. regeneration | D: regeneration. | |
Most crustaceans have separate sexes, so they reproduce sexually using what?
Here are the choices:
A. eggs and sperm
B. pod and eggs
C. eggs and pod
D. asexual reproduction | Most crustaceans have separate sexes, so they reproduce sexually using eggs and sperm. Many land crustaceans, such as the Christmas Island red crab, mate every season and return to the sea to release the eggs. Others, such as woodlice, lay their eggs on land when the environment is damp. In some crustaceans, the females keep the eggs until they hatch into free-swimming larvae. | A: eggs and sperm. |
Visible light is one type of this radiation?
Here are the choices:
A. neutron
B. Ionizing
C. Gamma
D. electromagnetic | Visible light is one type of electromagnetic radiation , which is a form of energy that exhibits wavelike behavior as it moves through space. Other types of electromagnetic radiation include gamma rays, x-rays, ultraviolet light, infrared light, microwaves, and radio waves. The figure below shows the electromagnetic spectrum , which is all forms of electromagnetic radiation. Notice that visible light makes up only a very, very small portion of the entire electromagnetic spectrum. All electromagnetic radiation moves through a vacuum at a constant speed of 2.998 × 10 8 m/s. While the presence of air molecules slows the speed of light by a very small amount, we will use the value of 3.00 × 10 8 m/s as the speed of light in air. | D: electromagnetic. |
Double-replacement reactions generally occur between substances in what kind of solution?
Here are the choices:
A. saline
B. solid
C. reactive
D. aqueous | In this reaction, and are positively-charged cations, while and are negatively-charged anions. Double-replacement reactions generally occur between substances in aqueous solution. In order for a reaction to occur, one of the products is usually a solid precipitate, a gas, or a molecular compound such as water. | D: aqueous. |
What happens to the recessive traits in the offspring of a hybridization?
Here are the choices:
A. they dominate
B. remain recessive
C. they disappear
D. they replicate | Upon compiling his results for many thousands of plants, Mendel concluded that the characteristics could be divided into expressed and latent traits. He called these, respectively, dominant and recessive traits. Dominant traits are those that are inherited unchanged in a hybridization. Recessive traits become latent, or disappear, in the offspring of a hybridization. The recessive trait does, however, reappear in the progeny of the hybrid offspring. An example of a dominant trait is the violet-flower trait. For this same characteristic (flower color), white-colored flowers are a recessive trait. The fact that the recessive trait reappeared in the F2 generation meant that the traits remained separate (not blended) in the plants of the F1 generation. Mendel also proposed that plants possessed two copies of the trait for the flower-color characteristic, and that each parent transmitted one of its two copies to its offspring, where they came together. Moreover, the physical observation of a dominant trait could mean that the genetic composition of the organism included two dominant versions of the characteristic or that it included one dominant and one recessive version. Conversely, the observation of a recessive trait meant that the organism lacked any dominant versions of this characteristic. | C: they disappear. |
What is a small, spherical compartment separated by at least one lipid layer from the cytosol?
Here are the choices:
A. vesicle
B. cortex
C. capillary
D. cuticle | A vesicle is a small, spherical compartment that is separated from the cytosol by at least one lipid bilayer. Many vesicles are made in the Golgi apparatus and the endoplasmic reticulum, or are made from parts of the cell membrane by endocytosis. Vesicles can also fuse with the cell membrane and release their contents to the outside. This process is called exocytosis. In addition to the Golgi apparatus and ER, vesicles can also fuse with other organelles within the cell. | A: vesicle. |
What term is used to describe is the increased or decreased speed of movement of an organism in response to a stimulus?
Here are the choices:
A. orthokinesis
B. klinokinesis
C. telekinesis
D. brownian motion | Kinesis and Taxis Another activity or movement of innate behavior is kinesis, or the undirected movement in response to a stimulus. Orthokinesis is the increased or decreased speed of movement of an organism in response to a stimulus. Woodlice, for example, increase their speed of movement when exposed to high or low temperatures. This movement, although random, increases the probability that the insect spends less time in the unfavorable environment. Another example is klinokinesis, an increase in turning behaviors. It is exhibited by bacteria such as E. coli which, in association with orthokinesis, helps the organisms randomly find a more hospitable environment. A similar, but more directed version of kinesis is taxis: the directed movement towards or away from a stimulus. This movement can be in response to light (phototaxis), chemical signals (chemotaxis), or gravity (geotaxis) and can be directed toward (positive) or away (negative) from the source of the stimulus. An example of a positive chemotaxis is exhibited by the unicellular protozoan Tetrahymena thermophila. This organism swims using its cilia, at times moving in a straight line, and at other times making turns. The attracting chemotactic agent alters the frequency of turning as the organism moves directly toward the source, following the increasing concentration gradient. Fixed Action Patterns A fixed action pattern is a series of movements elicited by a stimulus such that even when the stimulus is removed, the pattern goes on to completion. An example of such a behavior occurs in the three-spined stickleback, a small freshwater fish (Figure 45.34). Males of this species develop a red belly during breeding season and show instinctual aggressiveness to other males during this time. In laboratory experiments, researchers exposed such fish to objects that in no way resemble a fish in their shape, but which were painted red on their lower halves. The male sticklebacks responded aggressively to the objects just as if they were real male sticklebacks. | A: orthokinesis. |
How can natural resources be classified from a human point of view?
Here are the choices:
A. renewable or reversible
B. renewable or nonrenewable
C. present or nonrenewable
D. recyclable or reusable | From a human point of view, natural resources can be classified as either renewable or nonrenewable. | B: renewable or nonrenewable. |
What are the two types of endoplasmic reticulum?
Here are the choices:
A. rough & thick
B. rough & smooth
C. rough & thin
D. thick & smooth | There are two types of endoplasmic reticulum. They are called rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER). Both types are shown in Figure below . | B: rough & smooth. |
We know from what type of waves produced by earthquakes that parts of the interior of the earth are liquid?
Here are the choices:
A. seismic
B. kinetic
C. electromagnetic
D. volcanic | We know from seismic waves produced by earthquakes that parts of the interior of the Earth are liquid. Shear or transverse waves cannot travel through a liquid and are not transmitted through the Earth’s core. Yet compression or longitudinal waves can pass through a liquid and do go through the core. From this information, the temperature of the interior can be 9 estimated. As noticed, the interior should have cooled more from its initial temperature in the 4.5×10 years since its 9 formation. In fact, it should have taken no more than about 10 years to cool to its present temperature. What is keeping it hot? The answer seems to be radioactive decay of primordial elements that were part of the material that formed the Earth (see the blowup in Figure 31.26). Nuclides such as 238 U and 40 K have half-lives similar to or longer than the age of the Earth, and their decay still contributes energy to the interior. Some of the primordial radioactive nuclides have unstable decay products that also release energy— 238 U has a long decay chain of these. Further, there were more of these primordial radioactive nuclides early in the life of the Earth, and thus the activity and energy contributed were greater then (perhaps by an order of magnitude). The amount of power created by these decays per cubic meter is very small. However, since a huge volume of material lies deep below the surface, this relatively small amount of energy cannot escape quickly. The power produced near the surface has much less distance to go to escape and has a negligible effect on surface temperatures. | A: seismic. |
Radiocarbon is useful for dating relatively young materials with what element as their base?
Here are the choices:
A. oxygen
B. hydrogen
C. carbon
D. nitrogen | Radiocarbon is useful for relatively young, carbon-based materials. Other longer-lived isotopes are good for older rocks and minerals. | C: carbon. |
Why are eutherian mammals sometimes called placental mammals?
Here are the choices:
A. reacts placental connection
B. identical placental connection
C. complex placental connection
D. minor placental connection | Eutherians are the most widespread of the mammals, occurring throughout the world. There are several groups of eutherians, including Insectivora, the insect eaters; Edentata, the toothless anteaters; Rodentia, the rodents; Chiroptera, the bats; Cetacea, the aquatic mammals including whales; Carnivora, carnivorous mammals including dogs, cats, and bears; and Primates, which includes humans. Eutherian mammals are sometimes called placental mammals, because all species have a complex placenta that connects a fetus to the mother, allowing for gas, fluid, waste, and nutrient exchange. While other mammals may possess a less complex placenta or briefly have a placenta, all eutherians have a complex placenta during gestation. Primates Order Primates of class Mammalia includes lemurs, tarsiers, monkeys, and the apes, which include humans. Non-human primates live primarily in tropical or subtropical regions of South America, Africa, and Asia. They range in size from the mouse lemur at 30 grams (1 ounce) to the mountain gorilla at 200 kilograms (441 pounds). The characteristics and evolution of primates are of particular interest to us as they allow us to understand the evolution of our own species. All primate species have adaptations for climbing trees, as they all descended from tree-dwellers, although not all species are arboreal. This arboreal heritage of primates resulted in hands and feet that are adapted for brachiation, or climbing and swinging through trees. These adaptations include, but are not limited to 1) a rotating shoulder joint, 2) a big toe that is widely separated from the other toes and thumbs that are widely separated from fingers (except humans), which allow for gripping branches, and 3) stereoscopic vision, two overlapping visual fields, which allows for the depth perception necessary to gauge distance. Other characteristics of primates are brains that are larger than those of many other mammals, claws that have been modified into flattened nails, typically only one offspring per pregnancy, and a trend toward holding the body upright. Order Primates is divided into two groups: prosimians and anthropoids. Prosimians include the bush babies of Africa, the lemurs of Madagascar, and the lorises, pottos, and tarsiers of Southeast Asia. Anthropoids include monkeys, lesser apes, and great apes (Figure 15.47). In general, prosimians tend to be nocturnal, smaller in size than anthropoids, and have relatively smaller brains compared to anthropoids. | C: complex placental connection. |
What is the name for the division of the cytoplasm in eukaryotic cells, resulting in two genetically identical daughter cells?
Here are the choices:
A. vegetative division
B. metamorphosis
C. cytokinesis
D. mitosis | The second major step is cytokinesis. As in prokaryotic cells, the cytoplasm must divide. Cytokinesis is the division of the cytoplasm in eukaryotic cells, resulting in two genetically identical daughter cells. | C: cytokinesis. |
How can you prevent food allergy symptoms?
Here are the choices:
A. avoid offending foods
B. antiviral drugs
C. antioxidants
D. stem cell therapy | Common digestive system problems include foodborne illness and food allergies. Following healthy food-handling practices may decrease your risk of foodborne illness. Food allergy symptoms can be prevented by avoiding the offending foods. | A: avoid offending foods. |
Ground tissue forms the interior of the stem. the large central vacuoles of ground tissue cells fill with water to support the plant. the cells may also store what?
Here are the choices:
A. energy
B. Water
C. fuel
D. food | Ground tissue forms the interior of the stem. The large central vacuoles of ground tissue cells fill with water to support the plant. The cells may also store food. | D: food. |
Insect wings are part of the exoskeleton and attached to the what?
Here are the choices:
A. head
B. thorax
C. neck
D. spines | Insects generally have two pairs of wings for flight. Wings are part of the exoskeleton and attached to the thorax. Insect wings show a lot of variation. As you can see in Figure below , butterfly wings are paper-thin, whereas beetle wings are like armor. Not all insect wings work the same way, either. They differ in how the muscles are attached and whether the two pairs of wings work independently or together. Besides flight, wings serve other functions. They may protect the body (beetles), communicate visually with other insects (butterflies), or produce sounds to attract mates (katydids). | B: thorax. |
What was the informal female name given to the adult fossil found in ethiopia and thought to be over 3 million years old?
Here are the choices:
A. alice
B. linda
C. lucy
D. aunt | footprints, similar to those of modern humans, were found in Laetoli, Tanzania and dated to 3.6 million years ago. They showed that hominins at the time of Australopithecus were walking upright. There were a number of Australopithecus species, which are often referred to as australopiths. Australopithecus anamensis lived about 4.2 million years ago. More is known about another early species, Australopithecus afarensis, which lived between 3.9 and 2.9 million years ago. This species demonstrates a trend in human evolution: the reduction of the dentition and jaw in size. afarensis (Figure 29.42) had smaller canines and molars compared to apes, but these were larger than those of modern humans. Its brain size was 380–450 cubic centimeters, approximately the size of a modern chimpanzee brain. It also had prognathic jaws, which is a relatively longer jaw than that of modern humans. In the mid-1970s, the fossil of an adult female A. afarensis was found in the Afar region of Ethiopia and dated to 3.24 million years ago (Figure 29.43). The fossil, which is informally called “Lucy,” is significant because it was the most complete australopith fossil found, with 40 percent of the skeleton recovered. | C: lucy. |
What is the term for a formula that shows the elements in a compound in their lowest whole-number ratio?
Here are the choices:
A. Dwarf Formula
B. empirical formula
C. intrinsic formula
D. measured formula | An empirical formula is a formula that shows the elements in a compound in their lowest whole-number ratio. Glucose is an important simple sugar that cells use as their primary source of energy. Its molecular formula is C 6 H 12 O 6 . Since each of the subscripts is divisible by 6, the empirical formula for glucose is CH 2 O. When chemists analyze an unknown compound, often the first step is to determine its empirical formula. There are a great many compounds whose molecular and empirical formulas are the same. If the molecular formula cannot be simplified into a smaller whole-number ratio, as in the case of H 2 O or P 2 O 5 , then the empirical formula is also the molecular formula. | B: empirical formula. |
What is defined as the spreading of white light into its full spectrum of wavelengths?
Here are the choices:
A. saturation
B. dispersion
C. combustion
D. immersion | We see about six colors in a rainbow—red, orange, yellow, green, blue, and violet; sometimes indigo is listed, too. Those colors are associated with different wavelengths of light, as shown in Figure 25.22. When our eye receives pure-wavelength light, we tend to see only one of the six colors, depending on wavelength. The thousands of other hues we can sense in other situations are our eye’s response to various mixtures of wavelengths. White light, in particular, is a fairly uniform mixture of all visible wavelengths. Sunlight, considered to be white, actually appears to be a bit yellow because of its mixture of wavelengths, but it does contain all visible wavelengths. The sequence of colors in rainbows is the same sequence as the colors plotted versus wavelength in Figure 25.22. What this implies is that white light is spread out according to wavelength in a rainbow. Dispersion is defined as the spreading of white light into its full spectrum of wavelengths. More technically, dispersion occurs whenever there is a process that changes the direction of light in a manner that depends on wavelength. Dispersion, as a general phenomenon, can occur for any type of wave and always involves wavelength-dependent processes. Dispersion Dispersion is defined to be the spreading of white light into its full spectrum of wavelengths. | B: dispersion. |
What is used in the growth, development, functioning and reproduction of all known living organisms and many viruses?
Here are the choices:
A. viruses
B. enzymes
C. dna
D. bacteria | In 1966, Francis Crick proposed the Wobble Hypothesis which explained that the degeneracy of the genetic code is caused by the structure of the anticodon of tRNA. The anticodon is a three base sequence on the tRNA complementary to the codon on the mRNA. Each tRNA binds to a specific amino acid, but the anticodons of some tRNA molecules can bind to two or three different codons. This flexibility of the anticodon is caused by the less stringent 5' base on the anticodon loop, also referred to as the wobble base, which binds to the 3' base on the mRNA. Only the first two nucleotides are stringent and spatially confined for the decoding of the mRNA codon into an amino acid. This explains why degenerate codons often differ in the third position, as depicted in Figure above . For example, the amino acid alanine is coded by codons GCU, GCC, GCA and GCG. The wobble movement of the base in the 5' anticodon position is necessary for this degenerate capability. | C: dna. |
When methane burns, what is produced along with carbon dioxide?
Here are the choices:
A. nitrogen
B. hydrogen
C. water
D. oxygen | Compounds can also react with oxygen, possibly creating oxides of more than one element. When methane burns, carbon dioxide and water are produced. | C: water. |
What helps pumice float in water?
Here are the choices:
A. gravity
B. gas bubble holes
C. high density
D. large mass | Some extrusive igneous rocks cool so rapidly that crystals do not develop at all. These form a glass, such as obsidian. Others, such as pumice, contain holes where gas bubbles were trapped in the lava. The holes make pumice so light that it actually floats in water. The most common extrusive igneous rock is basalt. It is the rock that makes up the ocean floor. Shown below are three types of extrusive igneous rocks ( Figure below ). | B: gas bubble holes. |
What land mammal has the longest gestation period?
Here are the choices:
A. Giraffe
B. Rhino
C. african elephant
D. Asian elephant | 43.5 | Human Pregnancy and Birth By the end of this section, you will be able to: • Explain fetal development during the three trimesters of gestation • Describe labor and delivery • Compare the efficacy and duration of various types of contraception • Discuss causes of infertility and the therapeutic options available Pregnancy begins with the fertilization of an egg and continues through to the birth of the individual. The length of time of gestation varies among animals, but is very similar among the great apes: human gestation is 266 days, while chimpanzee gestation is 237 days, a gorilla’s is 257 days, and orangutan gestation is 260 days long. The fox has a 57-day gestation. Dogs and cats have similar gestations averaging 60 days. The longest gestation for a land mammal is an African elephant at 640 days. The longest gestations among marine mammals are the beluga and sperm whales at 460 days. | C: african elephant. |
What sustains the fetus while it grows inside the mother’s uterus?
Here are the choices:
A. mitochondria
B. placenta
C. endometrium
D. bacteria | Placental mammals get their name from the placenta. This is a spongy structure that develops during pregnancy only in placental mammals. You can see where a human placenta forms in Figure below . The placenta sustains the fetus while it grows inside the mother’s uterus. It consists of membranes and blood vessels from both mother and fetus. It allows substances to pass between the mother’s blood and that of the fetus. The fetus gets oxygen and nutrients from the mother. It passes carbon dioxide and other wastes to the mother. | B: placenta. |
Two kinds of sex hormones are of particular importance in females: progesterone, which prepares the uterus for pregnancy and prevents the further release of eggs from the ovaries during pregnancy, and the estrogens, which are mainly responsible for the development of female secondary sexual characteristics, such as breast development and increased deposition of this?
Here are the choices:
A. fat
B. muscle
C. blood
D. bone | characteristics of males, or the development of the male genital organs and the continuous production of sperm. Androgens are also responsible for the development of secondary male characteristics, such as facial hair, deep voice, and muscle strength. Two kinds of sex hormones are of particular importance in females: progesterone, which prepares the uterus for pregnancy and prevents the further release of eggs from the ovaries during pregnancy, and the estrogens, which are mainly responsible for the development of female secondary sexual characteristics, such as breast development and increased deposition of fat tissue in the breasts, the buttocks, and the thighs. Both males and females produce androgens and estrogens, differing in the amounts of secreted hormones rather than in the presence or absence of one or the other. Sex hormones, both natural and synthetic, are sometimes used therapeutically. For example, a woman who has had her ovaries removed may be given female hormones to compensate. Some of the earliest chemical compounds employed in cancer chemotherapy were sex hormones. For example, estrogens are one treatment option for prostate cancer because they block the release and activity of testosterone. Testosterone enhances prostate cancer growth. Sex hormones are also administered in preparation for sex-change operations, to promote the development of the proper secondary sexual characteristics. Oral contraceptives are synthetic derivatives of the female sex hormones; they work by preventing ovulation. | A: fat. |
Zoonotic pathogens are transferred from what to what?
Here are the choices:
A. animals to humans
B. animals to animals
C. humans to animals
D. humans to humans | A: animals to humans. | |
Restriction enzymes or restriction endonucleases are prokaryotic enzymes that recognize and cut what at specific sequences?
Here are the choices:
A. dna
B. mitochondria
C. bacteria
D. rna | Restriction enzymes or restriction endonucleases are prokaryotic enzymes that recognize and cut DNA at specific sequences, called restriction sites. It is believed that they evolved as a defense mechanism against foreign DNA, such as viral DNA. Over 3,000 restriction enzymes have been identified. Some of the more common restriction enzymes are shown in the table below, where up and down arrows show the sites of cleavage. Restriction enzymes are named based on the prokaryotic organism they are isolated from. For example, those isolated from Escherichia coli would begin with Eco. As the Table below shows, digestion with the restriction enzymes will result in overlapping or blunt ends. EcoRI produces overlapping "sticky" ends: the enzyme cleaves between the G and A on both strands. On the other hand, SmaII restriction enzyme cleavage produces "blunt" ends. The enzyme cleaves between the G and C on both strands. | A: dna. |
What are chemical reactions represented by?
Here are the choices:
A. liquid equations
B. nuclear equations
C. chemical equations
D. carbon equations | A chemical reaction occurs when some substances change chemically to other substances. Chemical reactions are represented by chemical equations. Consider a simple chemical reaction, the burning of methane. In this reaction, methane (CH 4 ) combines with oxygen (O 2 ) in the air and produces carbon dioxide (CO 2 ) and water vapor (H 2 O). The reaction is represented by the following chemical equation:. | C: chemical equations. |
The length of the sloped surface of a ramp is referred to as what?
Here are the choices:
A. input distance
B. accumulation distance
C. output distance
D. furlong | Consider the simple ramp in Figure below . A ramp can be used to raise an object up off the ground. The input distance is the length of the sloped surface of the ramp. The output distance is the height of the ramp, or the vertical distance the object is raised. Therefore, the ideal mechanical advantage of the ramp is:. | A: input distance. |
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