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Meiosis and what process are both preceded by one round of dna replication; however, they differ in producing haploid or diploid daughter cells?
Here are the choices:
A. mitosis
B. photosynthesis
C. cloning
D. fertilization | Figure 7.6 Meiosis and mitosis are both preceded by one round of DNA replication; however, meiosis includes two nuclear divisions. The four daughter cells resulting from meiosis are haploid and genetically distinct. The daughter cells resulting from mitosis are diploid and identical to the parent cell. | A: mitosis. |
In their pure form, all elements have an oxidation number of what?
Here are the choices:
A. zero
B. 7
C. 3
D. 2 | All elements have an oxidation number of zero in their pure form. | A: zero. |
What is a close relationship between two species in which at least one species benefits called?
Here are the choices:
A. parasitic
B. competition
C. symbiosis
D. morphogenesis | Symbiosis is a close relationship between two species in which at least one species benefits. For the other species, the relationship may be positive, negative, or neutral. There are three basic types of symbiosis: mutualism, commensalism, and parasitism. | C: symbiosis. |
Multiple sclerosis, huntington’s disease, parkinson’s disease, and alzheimer’s disease are example of diseases of which body system?
Here are the choices:
A. lymphatic system
B. muscular system
C. circulatory system
D. nervous system | There are many other nervous system diseases. They include multiple sclerosis, Huntington’s disease, Parkinson’s disease, and Alzheimer’s disease. However, these diseases rarely, if ever, occur in young people. Their causes and symptoms are listed below ( Table below ). The diseases have no known cure, but medicines may help control their symptoms. | D: nervous system. |
What includes the living organisms in an area and the non-living aspects of the environment?
Here are the choices:
A. habitat
B. outpost
C. degradation
D. ecosystem | An ecosystem includes the living organisms (all the populations) in an area and the non-living aspects of the environment ( Figure below ). An ecosystem is made of the biotic and abiotic factors in an area. | D: ecosystem. |
Bacteria may become untreatable if they develop what in response to multiple antibiotics?
Here are the choices:
A. acceptance
B. weakness
C. resistance
D. affinity | Evasion of the Immune System by Pathogens It is important to keep in mind that although the immune system has evolved to be able to control many pathogens, pathogens themselves have evolved ways to evade the immune response. An example already mentioned is in Mycobactrium tuberculosis, which has evolved a complex cell wall that is resistant to the digestive enzymes of the macrophages that ingest them, and thus persists in the host, causing the chronic disease tuberculosis. This section briefly summarizes other ways in which pathogens can “outwit” immune responses. But keep in mind, although it seems as if pathogens have a will of their own, they do not. All of these evasive “strategies” arose strictly by evolution, driven by selection. Bacteria sometimes evade immune responses because they exist in multiple strains, such as different groups of Staphylococcus aureus. aureus is commonly found in minor skin infections, such as boils, and some healthy people harbor it in their nose. One small group of strains of this bacterium, however, called methicillin-resistant Staphylococcus aureus, has become resistant to multiple antibiotics and is essentially untreatable. Different bacterial strains differ in the antigens on their surfaces. The immune response against one strain (antigen) does not affect the other; thus, the species survives. Another method of immune evasion is mutation. Because viruses’ surface molecules mutate continuously, viruses like influenza change enough each year that the flu vaccine for one year may not protect against the flu common to the next. New vaccine formulations must be derived for each flu season. Genetic recombination—the combining of gene segments from two different pathogens—is an efficient form of immune evasion. For example, the influenza virus contains gene segments that can recombine when two different viruses infect the same cell. Recombination between human and pig influenza viruses led to the 2010 H1N1 swine flu outbreak. Pathogens can produce immunosuppressive molecules that impair immune function, and there are several different types. Viruses are especially good at evading the immune response in this way, and many types of viruses have been shown to suppress the host immune response in ways much more subtle than the wholesale destruction caused by HIV. | C: resistance. |
What grows through blue cheese that gives it the distinctive appearance and flavor?
Here are the choices:
A. Viruses
B. Roots
C. fungus
D. Bacteria | Humans have collected and grown mushrooms for food for thousands of years. Figure below shows some of the many types of mushrooms that people eat. Yeasts are used in bread baking and brewing alcoholic beverages. Other fungi are used in fermenting a wide variety of foods, including soy sauce, tempeh, and cheeses. Blue cheese has its distinctive appearance and flavor because of the fungus growing though it (see Figure below ). | C: fungus. |
The two main types of phagocytic cells in the mammalian body are neutrophils and what other?
Here are the choices:
A. macrophages
B. leukocytes
C. histones
D. eukaryotes | A: macrophages. | |
What is aggravated by practices such as logging, mining, construction, and paving surfaces?
Here are the choices:
A. soil erosion
B. global warming
C. seismic activity
D. water pollution | Logging, mining, construction, and paving surfaces are some of the ways that soil erosion increases. | A: soil erosion. |
What type of hydrocarbon is coal?
Here are the choices:
A. mineral
B. liqued
C. gas
D. solid | Coal is a solid hydrocarbon. Coal is useful as a fuel, especially for generating electricity. Coal is relatively inexpensive and abundant. Developing nations, like China, rely heavily on coal. Around the world, coal is the largest source of energy for electricity. | D: solid. |
What chemicals in the liver support glucose homeostasis?
Here are the choices:
A. cytosol and insulin
B. Force and insulin
C. lactobacilli and insulin
D. glucagon and insulin | D: glucagon and insulin. | |
When resources become limiting, populations follow a logistic growth curve in which the size will level off at a point called what?
Here are the choices:
A. carrying capacity
B. full capacity
C. containing capacity
D. believed capacity | 19.2 Population Growth and Regulation Populations with unlimited resources grow exponentially—with an accelerating growth rate. When resources become limiting, populations follow a logistic growth curve in which population size will level off at the carrying capacity. Populations are regulated by a variety of density-dependent and density-independent factors. Life-history characteristics, such as age at first reproduction or numbers of offspring, are characteristics that evolve in populations just as anatomy or behavior can evolve over time. The model of r- and K-selection suggests that characters, and possibly suites of characters, may evolve adaptations to population stability near the carrying capacity (K-selection) or rapid population growth and collapse (r-selection). Species will exhibit adaptations somewhere on a continuum between these two extremes. | A: carrying capacity. |
Along with climate, this also influences the type of vegetation that can grow in the region?
Here are the choices:
A. fertilizer use
B. soil type
C. population density
D. gravity | Soil type also influences the type of vegetation that can grow in the region. We can identify climate types by the types of plants that grow there. | B: soil type. |
What is defined as anything that takes up space and has mass?
Here are the choices:
A. electrons
B. elements
C. matter
D. atoms | C: matter. | |
What is the name of the simplest carbon molecule?
Here are the choices:
A. graphite
B. Buckminsterfullerine
C. methane
D. butane | Figure 2.13 Carbon can form four covalent bonds to create an organic molecule. The simplest carbon molecule is methane (CH4), depicted here. | C: methane. |
Hyperparathyroidism results from an overproduction of what?
Here are the choices:
A. inhibited hormone
B. tharayroid hormone
C. elevated hormone
D. parathyroid hormone | Hyperparathyroidism results from an overproduction of parathyroid hormone. This results in excessive calcium being removed from bones and introduced into blood circulation, producing structural weakness of the bones, which can lead to deformation and fractures, plus nervous system impairment due to high blood calcium levels. Hypoparathyroidism, the underproduction of PTH, results in extremely low levels of blood calcium, which causes impaired muscle function and may result in tetany (severe sustained muscle contraction). The hormone calcitonin, which is produced by the parafollicular or C cells of the thyroid, has the opposite effect on blood calcium levels as does PTH. Calcitonin decreases blood calcium levels by inhibiting osteoclasts, stimulating osteoblasts, and stimulating calcium excretion by the kidneys. This results in calcium being added to the bones to promote structural integrity. Calcitonin is most important in children (when it stimulates bone growth), during pregnancy (when it reduces maternal bone loss), and during prolonged starvation (because it reduces bone mass loss). In healthy nonpregnant, unstarved adults, the role of calcitonin is unclear. | D: parathyroid hormone. |
What is formed when different gases are confined to the same container?
Here are the choices:
A. particulate mixture
B. linear mixture
C. homogeneous mixture
D. compact mixture | Gases mix homogeneously when confined to same container. When several gases are added to a container, the individual gas particles mix freely, forming a homogeneous mixture in which each type of gas is randomly distributed throughout all the available volume. | C: homogeneous mixture. |
What property of fluids causes something to stay on or near the surface of water?
Here are the choices:
A. weight
B. strength
C. density
D. buoyancy | The fishing float in Figure below bobs on the surface of the water. The fish in the figure is suspended in the water near the surface. Why do the float and fish stay on or near the surface? Why don’t they sink? The answer is buoyancy, another property of fluids. | D: buoyancy. |
What are the tiny sacs in the lungs where gas exchange takes place?
Here are the choices:
A. ganglion
B. alveoli
C. chambers
D. vacuoles | Pneumonia is an illness that occurs when the alveoli, the tiny sacs in the lungs where gas exchange takes place, become inflamed and filled with fluid. When a person has pneumonia, gas exchange cannot occur properly across the alveoli. Pneumonia can be caused by many things. Infection by bacteria, viruses, fungi, or parasites can cause pneumonia. An injury caused by chemicals or a physical injury to the lungs can also cause pneumonia. Symptoms of pneumonia include cough, chest pain, fever, and difficulty breathing. Treatment depends on the cause of pneumonia. Bacterial pneumonia is treated with antibiotics. | B: alveoli. |
What is the stage between a zygote and polyp?
Here are the choices:
A. egg
B. worm
C. larva
D. pupa | Cnidarians in the polyp form usually reproduce asexually. One type of asexual reproduction in polyps leads to the formation of new medusae. Medusae usually reproduce sexually with sperm and eggs. Fertilization forms a zygote. The zygote develops into a larva, and the larva develops into a polyp. There are many variations on this general life cycle. Obviously, species that exist only as polyps or medusae have a life cycle without the other form. | C: larva. |
What is the term for a particle outside the nucleus of an atom that has a negative electric charge?
Here are the choices:
A. neutron
B. ion
C. electron
D. proton | An electron is a particle outside the nucleus of an atom that has a negative electric charge. The charge of an electron is opposite but equal to the charge of a proton. Atoms have the same number of electrons as protons. As a result, the negative and positive charges "cancel out. " This makes atoms electrically neutral. For example, a carbon atom has six electrons that "cancel out" its six protons. | C: electron. |
Scientists goal is develop nuclear fusion power plants, where the energy from fusion of hydrogen nuclei can be converted to what?
Here are the choices:
A. wind
B. electricity
C. oil
D. gasoline | Scientists are searching for ways to create controlled nuclear fusion reactions on Earth. Their goal is develop nuclear fusion power plants, where the energy from fusion of hydrogen nuclei can be converted to electricity. How this might work is shown in Figure below . | B: electricity. |
In which state of matter are particles completely separate from one another?
Here are the choices:
A. solid state
B. liquid state
C. phosphorus state
D. gaseous state | Most substances may exist in any of the three common states of matter. In the gaseous state, the molecular motion has completely overcome any attraction between the particles and the particles are totally separate from each other. There are large spaces between the particles and they move large distances between collisions. In the liquid state, the molecular motion and the molecular attractions are more balanced. While the particles stay more or less in contact with each other, they are still free to move and can slide past one another easily. In the solid state, the attractive forces dominate. The particles are pulled together into a tightly packed pattern which does not allow the particles to pass each other. The molecular motion in this form is essentially reduced to vibration in place. Increasing the temperature of a substance means increasing the molecular motion (kinetic energy) of the molecules in the substance. The phase in which a substance exists is the result of a competition between attractive forces and molecular motion. | D: gaseous state. |
Van der waals forces are weak interactions between molecules that involve what?
Here are the choices:
A. photons
B. atoms
C. dipoles
D. particles | Van der Waals forces are weak interactions between molecules that involve dipoles. | C: dipoles. |
What part of the body does emphysema affect?
Here are the choices:
A. heart
B. brain
C. bones
D. lungs | Emphysema is a lung disease in which walls of the alveoli break down so less gas can be exchanged in the lungs (see Figure below ). This causes shortness of breath. The damage to the alveoli is usually caused by smoking and is irreversible. | D: lungs. |
What number is the sum of the numbers of protons and neutrons present in the nucleus of an atom?
Here are the choices:
A. nuclear number
B. mass total
C. mass number
D. combined number | As you learned in Chapter 1 "Introduction to Chemistry", the mass number is the sum of the numbers of protons and neutrons present in the nucleus of an atom. The mass number is an integer that is approximately equal to the numerical value of the atomic mass. Although the mass number is unitless, it is assigned units called atomic mass. | C: mass number. |
What kind of tool, often based on mathematical equations or computer simulations, helps us understand complex systems?
Here are the choices:
A. planes
B. panels
C. models
D. levels | Food Chains. These two food chains represent complex systems in nature. They make the systems easier to understand. These are simple conceptual models. Models of very complex systems are often based on mathematical equations or computer simulations. | C: models. |
An ecosystem consists of all the living things and what?
Here are the choices:
A. living environment
B. nonliving environment
C. phosphorescent environment
D. local environment | An ecosystem consists of all the living things ( biotic factors ) in a given area, together with the nonliving environment ( abiotic factors ). The nonliving environment includes water, sunlight, soil, and other physical factors. | B: nonliving environment. |
Mesophyll consists mainly of parenchyma cells specialized for what?
Here are the choices:
A. digestion
B. circulation
C. photosynthesis
D. respiration | C: photosynthesis. | |
Antibiotic drugs are usually effective in treating what kind of infections?
Here are the choices:
A. lethal
B. biological
C. bacterial
D. viral | Bacterial infections of urinary organs, especially the urinary bladder, are common. They are called urinary tract infections. Generally, they can be cured with antibiotic drugs. However, if they aren’t treated, they can lead to more serious infections and damage to the kidneys. | C: bacterial. |
What is earth’s geographic north pole also called?
Here are the choices:
A. true north
B. right north
C. vertical north
D. mere north | A compass needle lines up with Earth’s magnetic north pole. This is different from Earth’s geographic north pole, also called true north. The geographic north pole is the top of an imaginary line. This line is the axis around which Earth rotates. The geographic north pole is much like the spindle of a spinning top. The location of the geographic north pole does not change. However, the magnetic north pole shifts in location over time. Depending on where you live, you can correct for the difference between the two poles when you use a map and a compass ( Figure below ). | A: true north. |
What are the nonliving aspects of the environment called?
Here are the choices:
A. abiotic factors
B. nucleic factors
C. antibiotic factors
D. metastatic factors | Abiotic factors are the nonliving aspects of the environment. They include factors such as sunlight, soil, temperature, and water. | A: abiotic factors. |
Chemical reactions follow the laws of what?
Here are the choices:
A. photosynthesis
B. quantum physics
C. Newton
D. thermodynamics | Chemical reactions follow the laws of thermodynamics. | D: thermodynamics. |
What do you call a mixture of two or more substances in which dissolved particles are distributed evenly throughout?
Here are the choices:
A. liquid
B. water
C. concentrate
D. solution | A solution is a mixture of two or more substances in which dissolved particles are distributed evenly throughout the solution. The substance that dissolves in a solution is called the solute, and the substance that does the dissolving is called the solvent. The concentration of a solution is the amount of solute in a given amount of solution. A solution with a lot of dissolved solute has a high concentration and is called a concentrated solution. A solution with little dissolved solute has a low concentration and is called a dilute solution. | D: solution. |
What is the water that falls from the sky called?
Here are the choices:
A. condensation
B. precipitation
C. moisture
D. evaporation | Clouds are needed for precipitation. Precipitation is water that falls from the sky. This may fall as liquid water, mostly as rain . It may fall also as frozen water, such as snow. | B: precipitation. |
What returns blood from capillaries to an atrium?
Here are the choices:
A. the lymph system
B. the liver
C. arteries
D. veins | D: veins. | |
Hemolymph bathes organs directly in arthropods and most molluscs, due to an open type of what system?
Here are the choices:
A. reproductive
B. circulatory
C. nervous
D. pulmonary | B: circulatory. | |
According to the table, aluminum has an atomic number of 13. therefore, every aluminum atom has 13 protons in its what?
Here are the choices:
A. components
B. membrane
C. nucleus
D. processes | According to the table, aluminum has an atomic number of 13. Therefore, every aluminum atom has 13 protons in its nucleus. Iron has an atomic number of 26. Therefore, every iron atom has 26 protons in its nucleus. Carbon has an atomic number of 6. Therefore, every carbon atom has 6 protons in its nucleus. Saylor URL: http://www. saylor. org/books. | C: nucleus. |
Anemia, leukemia, hemophilia, and sickle-cell disease are examples of conditions that primarily affect what?
Here are the choices:
A. brain
B. heart
C. Lungs
D. blood | Some diseases affect mainly the blood or its components. They include anemia, leukemia, hemophilia, and sickle-cell disease. | D: blood. |
What kind of variation does a rate measure?
Here are the choices:
A. property to time
B. construction to time
C. value to time
D. environment to time | A rate is a measure of how some property varies with time. Speed is a familiar rate that expresses the distance traveled by an object in a given amount of time. Wage is a rate that represents the amount of money earned by a person working for a given amount of time. Likewise, the rate of a chemical reaction is a measure of how much reactant is consumed, or how much product is produced, by the reaction in a given amount of time. The rate of reaction is the change in the amount of a reactant or product per unit time. Reaction rates are therefore determined by measuring the time dependence of some property that can be related to reactant or product amounts. Rates of reactions that consume or produce gaseous substances, for example, are conveniently determined by measuring changes in volume or pressure. For reactions involving one or more colored substances, rates may be monitored via measurements of light absorption. For reactions involving aqueous electrolytes, rates may be measured via changes in a solution’s conductivity. For reactants and products in solution, their relative amounts (concentrations) are conveniently used for purposes of expressing reaction rates. If we measure the concentration of hydrogen peroxide, H2O2, in an aqueous solution, we find that it changes slowly over time as the H2O2 decomposes, according to the equation: 2H 2 O 2(aq) ⟶ 2H 2 O(l) + O 2(g) The rate at which the hydrogen peroxide decomposes can be expressed in terms of the rate of change of its concentration, as shown here: change in concentration of reactant time interval ⎡ ⎤ ⎡ ⎤ − ⎣H 2 O 2⎦ t ⎣H 2 O 2⎦ t 1 2 = − t2 − t1. | A: property to time. |
What is the name of the process that changes some chemical substances into others?
Here are the choices:
A. chemical reaction
B. acid reaction
C. hypodermic reaction
D. mixture | A chemical reaction is a process that changes some chemical substances into others. It involves breaking and forming chemical bonds. Types of chemical reactions include synthesis reactions and decomposition reactions. | A: chemical reaction. |
What is the term for the gases that surround a planet?
Here are the choices:
A. the atmosphere
B. galaxy
C. hemisphere
D. biosphere | An atmosphere is the gases that surround a planet. The early Earth had no atmosphere. Conditions were so hot that gases were not stable. | A: the atmosphere. |
Pressure and vibration are examples of what type of stimuli?
Here are the choices:
A. chemical
B. atmospheric
C. thermal
D. physical | Functional Receptor Types A third classification of receptors is by how the receptor transduces stimuli into membrane potential changes. Stimuli are of three general types. Some stimuli are ions and macromolecules that affect transmembrane receptor proteins when these chemicals diffuse across the cell membrane. Some stimuli are physical variations in the environment that affect receptor cell membrane potentials. Other stimuli include the electromagnetic radiation from visible light. For humans, the only electromagnetic energy that is perceived by our eyes is visible light. Some other organisms have receptors that humans lack, such as the heat sensors of snakes, the ultraviolet light sensors of bees, or magnetic receptors in migratory birds. Receptor cells can be further categorized on the basis of the type of stimuli they transduce. Chemical stimuli can be interpreted by a chemoreceptor that interprets chemical stimuli, such as an object’s taste or smell. Osmoreceptors respond to solute concentrations of body fluids. Additionally, pain is primarily a chemical sense that interprets the presence of chemicals from tissue damage, or similar intense stimuli, through a nociceptor. Physical stimuli, such as pressure and vibration, as well as the sensation of sound and body position (balance), are interpreted through a mechanoreceptor. Another physical stimulus that has its own type of receptor is temperature, which is sensed through a thermoreceptor that is either sensitive to temperatures above (heat) or below (cold) normal body temperature. | D: physical. |
In the chest, what divides as it enters the lungs to form the right and left bronchi?
Here are the choices:
A. trachea
B. thyroid
C. nerves
D. Aorta | In the chest, the trachea divides as it enters the lungs to form the right and left bronchi (bronchus, singular). These passages are covered with mucus and tiny hairs called cilia. The mucus traps any remaining particles in the air. The cilia move and sweep the particles and mucus toward the throat so they can be expelled from the body. | A: trachea. |
When does an oocyte complete meiosis?
Here are the choices:
A. after sperm penetration
B. prophase
C. metaphase
D. anaphase | A: after sperm penetration. | |
The electroplating process transfers metal from the anode to which part of the cell?
Here are the choices:
A. cathode
B. electrode
C. plasma
D. atom tube | The concentration of copper ions in the solution is effectively constant. This is because the electroplating process transfers metal from the anode to the cathode of the cell. Other metals commonly plated onto objects include chromium, gold, silver, and platinum. | A: cathode. |
Compression, tension and shear refer to what type of force that can cause rock to change?
Here are the choices:
A. gravity
B. stress
C. process
D. seismic force | Stress is the force applied to a rock, which can cause the rock to change. The three main types of stress go along with the three types of plate boundaries. Compression is common at convergent boundaries, tension at divergent boundaries, and shear at transform boundaries. | B: stress. |
Unlike the biological species concept, the ecological species concept can accommodate asexual as well as ________ species.
Here are the choices:
A. homologous
B. homosexual
C. artificial
D. sexual | D: sexual. | |
A basic function of cells includes obtaining what from glucose?
Here are the choices:
A. food
B. acids
C. proteins
D. energy | Obtaining energy from glucose is one of the basic functions of cells. Another basic function of living cells is dividing. | D: energy. |
What is the term for a test to see if a scientific explanation is right or wrong?
Here are the choices:
A. generation
B. invention
C. experiment
D. hypothesis | Scientists find answers using tests : When scientists want to answer a question, they search for evidence using experiments. An experiment is a test to see if their explanation is right or wrong. Evidence is made up of the observations a scientist makes during an experiment. To study the cause of death in the chimpanzees, scientists may give the chimps nutrients in the form of nuts, berries, and vitamins to see if they are dying from a lack of food. This test is the experiment. If fewer chimps die, then the experiment shows that the chimps may have died from not having enough food. This is the evidence. | C: experiment. |
When a solvent with a gas dissolved in it is heated, the kinetic energy of both the solvent and solute _________?
Here are the choices:
A. decreases
B. increases
C. generates
D. evaporates | Several substances – HCl, NH 3 , and SO 2 – have solubility that decreases as temperature increases. They are all gases at standard pressure. When a solvent with a gas dissolved in it is heated, the kinetic energy of both the solvent and solute increases. As the kinetic energy of the gaseous solute increases, its molecules have a greater tendency to escape the attraction of the solvent molecules and return to the gas phase. Therefore, the solubility of a gas decreases as the temperature increases. | B: increases. |
How does the bacteria look when seen with the naked eye?
Here are the choices:
A. dry smear
B. slimy smear
C. oily smear
D. slippery smear | With the naked eye, bacteria just look like a slimy smear on a petri dish. How can we study them in more detail? The invention of the microscope has allowed us to see bacteria, cells, and other things too small to be seen with the naked eye. | B: slimy smear. |
What is a device used to measure temperature changes during chemical processes called?
Here are the choices:
A. thermometer
B. calorimeter
C. alethiometer
D. altimeter | The subfield of thermochemistry studies the energy changes that occur over the course of various chemical reactions. We will first look at how these changes are measured and then go into quantitative descriptions of heat transfer. Calorimetry is a term used to describe the measurement of heat transfers, usually by monitoring changes in the temperature of an isolated system. A calorimeter is a device used to measure temperature changes during chemical processes. The simplest type of calorimeter is the constant-pressure device illustrated in Figure below . | B: calorimeter. |
Ebola is an example of a disease spread by what kind of infectious agent?
Here are the choices:
A. flus
B. virus
C. bacteria
D. colds | Ebola is a rare and deadly disease caused by infection with a strain of Ebola virus. The 2014 Ebola epidemic is the largest in history, affecting multiple countries in West Africa, including Guinea, Sierra Leone and Liberia. Ebola is spread through direct contact with blood and body fluids of a person infected by and already showing symptoms of Ebola. Ebola is not spread through the air, water, food, or mosquitoes. See Ebola virus disease at http://www. who. int/mediacentre/factsheets/fs103/en/ for additional information. | B: virus. |
The tiny hair present on mucus membranes is known as?
Here are the choices:
A. collagen
B. tissue
C. dendrites
D. cilia | Mucous membranes provide a mechanical barrier at body openings. They also line the respiratory, GI, urinary, and reproductive tracts. Mucous membranes secrete mucus , a slimy substance that traps pathogens. The membranes also have hair-like cilia. The cilia sweep mucus and pathogens toward body openings where they can be removed from the body. When you sneeze or cough, pathogens are removed from the nose and throat (see Figure below ). Tears wash pathogens from the eyes, and urine flushes pathogens out of the urinary tract. You can watch the sweeping action of cilia at the following link: http://mcdb. colorado. edu/courses/2115/units/Other/mucus%20animation. swf . | D: cilia. |
What elements do lipids primarily consist of?
Here are the choices:
A. helium, hydrogen , and oxygen
B. carbon, hydrogen, and oxygen
C. iron, hydrogen , and oxygen
D. silicon, hydrogen , and oxygen | Lipids are organic compounds that contain mainly carbon, hydrogen, and oxygen. They include substances such as fats and oils, as well as waxes, sterols, some vitamins (A, D, E and K) and phospholipids. Lipid molecules consist of fatty acids, with or without additional molecules. Fatty acids are organic compounds that have the general formula CH 3 (CH 2 ) n COOH, where n usually ranges from 2 to 28 and is always an even number. | B: carbon, hydrogen, and oxygen. |
Polychaetes make up a large and diverse group. which category do the majority of these worms fall into?
Here are the choices:
A. terrestrial
B. marine
C. amphibian
D. carnivorous | B: marine. | |
What is the main makeup of the cell membrane?
Here are the choices:
A. filaments
B. phospholipids
C. antibodies
D. glucose | You can see a model of the cell membrane in Figure below . The molecules that make up the cell membrane are mainly phospholipids. There are two layers of phospholipids. They are arranged so the lipid tails are on the inside of the membrane. They make the interior of the membrane hydrophobic, or "water fearing". The lipid heads point toward the outside of the membrane. The make the outer surfaces of the membrane hydrophilic, or "water loving". Different types of proteins are embedded in the lipid layers. The proteins are needed to help transport many substances across the membrane. | B: phospholipids. |
When a host attacks a parasitic bacteria, the bacteria release what to surround the cell wall?
Here are the choices:
A. layer of slime
B. protoplasma
C. bacteriophages
D. pathogens | Some bacteria depend on a host organism for energy and nutrients. These bacteria are known as parasites . If the host starts attacking the parasitic bacteria, the bacteria release a layer of slime that surrounds the cell wall. This slime offers an extra layer of protection. | A: layer of slime. |
Solutions can also become supersaturated , where the amount of solute dissolved exceeds what?
Here are the choices:
A. part solubility
B. its solubility
C. its concentration
D. its dissolution | Solutions can also become supersaturated , where the amount of solute dissolved exceeds its solubility. Supersaturation most commonly occurs when a saturated solution is slowly cooled. They occur frequently in geological and meteorological processes. Supersaturated systems are unstable, and eventually, the solute will precipitate until a saturated solution is regenerated. We can quantify supersaturation by looking at solubility curves. If the ratio of solute to solvent is above the saturation curve at the given temperature, the solution is supersaturated. If it is on the curve, the solution is saturated, and if it is below the curve, the solution is unsaturated. | B: its solubility. |
What is the biggest risk associated with using nuclear energy?
Here are the choices:
A. explosion
B. mutation
C. radiation
D. fire | The main concern over the use of nuclear energy is the risk of radiation. Accidents at nuclear power plants can release harmful radiation that endangers people and other living things. Even without accidents, the used fuel that is left after nuclear fission reactions is still radioactive and very dangerous. It takes thousands of years for it to decay until it no longer releases harmful radiation. Therefore, used fuel must be stored securely to protect people and other living things. You can learn more about the problem of radioactive waste at this URL: http://www. youtube. com/watch?v=OPQ97LVRuuM. | C: radiation. |
What property is the result of the force of gravity being opposed by the normal force?
Here are the choices:
A. weight
B. sound
C. light
D. density | For a full description of weight, look at Forces: Mass versus Weight. In sum, weight is the result of the force of gravity being opposed by the normal force. As we just learned, objects in orbit are in freefall; they have nothing exerting a normal force against them and thus no weight. | A: weight. |
What are the cliffs called which are created when waves erode a rocky shoreline, leaving a vertical wall of exposed rock layers?
Here are the choices:
A. wave-cut
B. widow-makers
C. wave - theory
D. shear face | Wave-cut cliffs form when waves erode a rocky shoreline. They create a vertical wall of exposed rock layers. | A: wave-cut. |
When boron10 absorbs a neutron, what does it emit?
Here are the choices:
A. light
B. particle
C. proteins
D. calcium | Boron neutron capture therapy is a potential treatment for many diseases. As the name implies, when boron10, one of the naturally occurring isotopes of boron, is bombarded with neutrons, it absorbs a neutron and emits an α particle. Write a balanced nuclear reaction for this reaction. One advantage of this process is that neutrons cause little damage on their own, but when they are absorbed by boron-10, they can cause localized emission of alpha radiation. Comment on the utility of this treatment and its potential difficulties. | B: particle. |
What is the most common life form in the ocean?
Here are the choices:
A. algae
B. plankton
C. kelp
D. coral | When you think of life in the ocean, do you think of fish? Actually, fish are not the most common life forms in the ocean. Plankton are the most common. Plankton make up one of three major groups of marine life. The other two groups are nekton and benthos. Figure below shows the three groups. | B: plankton. |
What circulates with the blood or hemolymph and are often contained within specialized cells
Here are the choices:
A. respiratory pigments
B. muscular pigments
C. fat pigments
D. structural pigments | A: respiratory pigments. | |
What are the two possible reduction products for brf3?
Here are the choices:
A. brf and br2
B. brf and brf4
C. brg and brf
D. brf2 and brf4 | redox reaction will occur. The only question is whether lead will be oxidized to Pb(II) or Pb(IV). Because BrF3 is a powerful oxidant and fluorine is able to stabilize high oxidation states of other elements, it is likely that PbF4 will be the product. The two possible reduction products for BrF3 are BrF and Br2. The actual product will likely depend on the ratio of the reactants used. With excess BrF3, we expect the more oxidized product (BrF). With lower ratios of oxidant to lead, we would probably obtain Br2 as the product. Exercise Predict the products of each reaction and write a balanced chemical equation for each reaction. | A: brf and br2. |
Normal blood is comprised of nearly half erythrocytes, which is another word for what cells?
Here are the choices:
A. white blood cells
B. plateletes
C. red blood cells
D. monocytes | Composition of Blood You have probably had blood drawn from a superficial vein in your arm, which was then sent to a lab for analysis. Some of the most common blood tests—for instance, those measuring lipid or glucose levels in plasma—determine which substances are present within blood and in what quantities. Other blood tests check for the composition of the blood itself, including the quantities and types of formed elements. One such test, called a hematocrit, measures the percentage of RBCs, clinically known as erythrocytes, in a blood sample. It is performed by spinning the blood sample in a specialized centrifuge, a process that causes the heavier elements suspended within the blood sample to separate from the lightweight, liquid plasma (Figure 18.2). Because the heaviest elements in blood are the erythrocytes, these settle at the very bottom of the hematocrit tube. Located above the erythrocytes is a pale, thin layer composed of the remaining formed elements of blood. These are the WBCs, clinically known as leukocytes, and the platelets, cell fragments also called thrombocytes. This layer is referred to as the buffy coat because of its color; it normally constitutes less than 1 percent of a blood sample. Above the buffy coat is the blood plasma, normally a pale, strawcolored fluid, which constitutes the remainder of the sample. The volume of erythrocytes after centrifugation is also commonly referred to as packed cell volume (PCV). In normal blood, about 45 percent of a sample is erythrocytes. The hematocrit of any one sample can vary significantly, however, about 36–50 percent, according to gender and other factors. Normal hematocrit values for females range from 37 to 47, with a mean value of 41; for males, hematocrit ranges from 42 to 52, with a mean of 47. The percentage of other formed elements, the WBCs and platelets, is extremely small so it is not normally considered with the hematocrit. So the mean plasma percentage is the percent of blood that is not erythrocytes: for females, it is approximately 59 (or 100 minus 41), and for males, it is approximately 53 (or 100 minus 47). | C: red blood cells. |
What type of intense storm is a system of winds that rotate around a low pressure center, resulting in swirling air that rises and cools to create clouds and precipitation?
Here are the choices:
A. monsoon
B. drought
C. cyclone
D. hurricane | Cyclones can be the most intense storms on Earth. A cyclone is a system of winds that rotate around a low pressure center. The swirling air rises and cools. This creates clouds and precipitation. | C: cyclone. |
Blood flows into the kidney through which artery?
Here are the choices:
A. renal artery
B. main artery
C. pulminary artery
D. blood artery | Blood flows into the kidney through the renal artery. The renal artery connects to capillaries inside the kidney. Capillaries and nephrons lie very close to each other in the kidney. | A: renal artery. |
Growth and development in humans is most rapid during what two stages?
Here are the choices:
A. flutter and adolescence
B. bounce and adolescence
C. teen and adults
D. infancy and adolescence | Growth and development are most rapid during infancy and slower throughout the rest of childhood until adolescence. | D: infancy and adolescence. |
What are used to write nuclear equations for radioactive decay?
Here are the choices:
A. special symbols
B. chemical symbols
C. energy symbols
D. nuclear symbols | Nuclear symbols are used to write nuclear equations for radioactive decay. Let’s consider an example. Uranium-238 undergoes alpha decay to become thorium-234. (The numbers following the chemical names refer to the number of protons plus neutrons. ) In this reaction, uranium-238 loses two protons and two neutrons to become the element thorium-234. The reaction can be represented by this nuclear equation:. | D: nuclear symbols. |
The pull of gravity is expressed as a force of what?
Here are the choices:
A. newtons
B. joule
C. volt
D. pascal | One force acting on you—and all the other objects on Earth—is gravity. Look at the physics book in the Figure below . Gravity pulls the book downward with a force of 20 Newtons. Why doesn’t the book fall to the ground? The table pushes upward on the book with the same amount of force. The combined force, or net force , acting on the book is 0 Newtons. That’s because upward and downward forces are balanced, so they cancel out. You can learn more about net force at this URL:. | A: newtons. |
What type of physics explains the behavior of visible light and electromagnetic waves?
Here are the choices:
A. Thermodynamics
B. statistics
C. optics
D. Quantum mechanics | We already know that visible light is the type of electromagnetic waves to which our eyes respond. That knowledge still leaves many questions regarding the nature of light and vision. What is color, and how do our eyes detect it? Why do diamonds sparkle? How does light travel? How do lenses and mirrors form images? These are but a few of the questions that are answered by the study of optics. Optics is the branch of physics that deals with the behavior of visible light and other electromagnetic waves. In particular, optics is concerned with the generation and propagation of light and its interaction with matter. What we have already learned about the generation of light in our study of heat transfer by radiation will be expanded upon in later topics, especially those on atomic physics. Now, we will concentrate on the propagation of light and its interaction with matter. It is convenient to divide optics into two major parts based on the size of objects that light encounters. When light interacts with an object that is several times as large as the light’s wavelength, its observable behavior is like that of a ray; it does not prominently display its wave characteristics. We call this part of optics “geometric optics. ” This chapter will concentrate on such situations. When light interacts with smaller objects, it has very prominent wave characteristics, such as constructive and destructive interference. Wave Optics will concentrate on such situations. | C: optics. |
The duodenum has a major role in regulating what digestive organ and its emptying?
Here are the choices:
A. respiratory
B. kidneys
C. skin
D. stomach | stretch receptors. This stimulates parasympathetic neurons to release acetylcholine, which then provokes increased secretion of gastric juice. Partially digested proteins, caffeine, and rising pH stimulate the release of gastrin from enteroendocrine G cells, which in turn induces parietal cells to increase their production of HCl, which is needed to create an acidic environment for the conversion of pepsinogen to pepsin, and protein digestion. Additionally, the release of gastrin activates vigorous smooth muscle contractions. However, it should be noted that the stomach does have a natural means of avoiding excessive acid secretion and potential heartburn. Whenever pH levels drop too low, cells in the stomach react by suspending HCl secretion and increasing mucous secretions. The intestinal phase of gastric secretion has both excitatory and inhibitory elements. The duodenum has a major role in regulating the stomach and its emptying. When partially digested food fills the duodenum, intestinal mucosal cells release a hormone called intestinal (enteric) gastrin, which further excites gastric juice secretion. This stimulatory activity is brief, however, because when the intestine distends with chyme, the enterogastric reflex inhibits secretion. One of the effects of this reflex is to close the pyloric sphincter, which blocks additional chyme from entering the duodenum. | D: stomach. |
What are misfolded versions of normal brain proteins?
Here are the choices:
A. prions
B. humans
C. protons
D. ribosomes | A: prions. | |
By impacting plant species and the animals they support, destruction of habitat threatens what event?
Here are the choices:
A. depletion
B. mutation
C. extinction
D. overpopulation | C: extinction. | |
What division of the nervous system controls involuntary activities that are not emergencies, such as the digestive organs breaking down food?
Here are the choices:
A. somatic nervous system
B. parasympathetic division
C. posterior division
D. central nervous system | The parasympathetic division controls involuntary activities that are not emergencies. For example, it controls the organs of your digestive system so they can break down the food you eat. | B: parasympathetic division. |
What occurs when a cold air mass runs into a warm air mass?
Here are the choices:
A. an occluded front
B. a stationary front
C. a snow day
D. a cold front | A cold front occurs when a cold air mass runs into a warm air mass. This is shown in Figure below . The cold air mass moves faster than the warm air mass and lifts the warm air mass out of its way. As the warm air rises, its water vapor condenses. Clouds form, and precipitation falls. If the warm air is very humid, precipitation can be heavy. Temperature and pressure differences between the two air masses cause winds. Winds may be very strong along a cold front. | D: a cold front. |
What are the tiny sacs in the lungs where gas exchange takes place?
Here are the choices:
A. alveoli
B. bronchi
C. ganglion
D. cilia | Alveoli are tiny sacs in the lungs where gas exchange takes place. | A: alveoli. |
What is the term for plants that lack vascular tissues, roots, leaves, seeds, and flowers?
Here are the choices:
A. chloroplasts
B. primates
C. conifers
D. bryophytes | Modern nonvascular plants are called bryophytes. There are about 17,000 bryophyte species. They include liverworts, hornworts, and mosses. Mosses are the most numerous group of bryophytes. You can see an example of moss in Figure below . Like the moss in the figure, most bryophytes are small. They lack not only vascular tissues. They also lack true roots, leaves, seeds, and flowers. Bryophytes live in moist habitats. Without the adaptations of vascular plants, bryophytes are not very good at absorbing water. They also need water to reproduce. | D: bryophytes. |
Why are continents unable to be pushed down into the mantle by plate boundaries?
Here are the choices:
A. gravity
B. buoyancy
C. surface tension
D. density | Most of the world’s largest mountains form as plates collide at convergent plate boundaries. Continents are too buoyant to get pushed down into the mantle. So when the plates smash together, the crust crumples upwards. This creates mountains. Folding and faulting in these collision zones makes the crust thicker. | B: buoyancy. |
What is it called when a new species arises without geographic separation?
Here are the choices:
A. quantum speciation
B. sympatric speciation
C. spontaneous evolution
D. Allopatric speciation | Less often, a new species arises without geographic separation. This is called sympatric speciation . The following example shows one way this can occur. | B: sympatric speciation. |
In an exothermic reaction, what, specifically, is released?
Here are the choices:
A. precipitation
B. humidity
C. water
D. heat | When methane gas is combusted, heat is released, making the reaction exothermic. Specifically, the combustion of 1 mol of methane releases 890.4 kilojoules of heat energy. This information can be shown as part of the balanced equation. | D: heat. |
What term describes diseases caused by abnormal cells in the body dividing uncontrollably?
Here are the choices:
A. diabetes
B. radiation
C. eczema
D. cancer | Diseases One of the most talked about diseases is skin cancer. Cancer is a broad term that describes diseases caused by abnormal cells in the body dividing uncontrollably. Most cancers are identified by the organ or tissue in which the cancer originates. One common form of cancer is skin cancer. The Skin Cancer Foundation reports that one in five Americans will experience some type of skin cancer in their lifetime. The degradation of the ozone layer in the atmosphere and the resulting increase in exposure to UV radiation has contributed to its rise. Overexposure to UV radiation damages DNA, which can lead to the formation of cancerous lesions. Although melanin offers some protection against DNA damage from the sun, often it is not enough. The fact that cancers can also occur on areas of the body that are normally not exposed to UV radiation suggests that there are additional factors that can lead to cancerous lesions. In general, cancers result from an accumulation of DNA mutations. These mutations can result in cell populations that do not die when they should and uncontrolled cell proliferation that leads to tumors. Although many tumors are benign (harmless), some produce cells that can mobilize and establish tumors in other organs of the body; this process is referred to as metastasis. Cancers are characterized by their ability to metastasize. | D: cancer. |
What is the molecule, dipeptide formed together by?
Here are the choices:
A. polymer acids
B. acetic acids
C. amino acids
D. rna acids | Amino acids join together to form a molecule called a dipeptide. The –OH from the carboxyl group of one amino acid combines with a hydrogen atom from the amino group of the other amino acid to produce water (blue). | C: amino acids. |
Did the the open circulatory systems of molluscs and arthropods arise dependently or independently of each other?
Here are the choices:
A. dependently
B. together
C. separately
D. independently | D: independently. | |
What kind of weathering is abrasion?
Here are the choices:
A. molecular
B. natural
C. electromagnetic
D. mechanical | Abrasion is another type of mechanical weathering. With abrasion, one rock bumps against another rock. Gravity causes abrasion as a rock tumbles down a slope. Moving water causes abrasion it moves rocks so that they bump against one another ( Figure below ). Strong winds cause abrasion by blasting sand against rock surfaces. Finally, the ice in glaciers cause abrasion. Pieces of rock embedded in ice at the bottom of a glacier scrape against the rock below. If you have ever collected beach glass or pebbles from a stream, you have witnessed the work of abrasion. | D: mechanical. |
What are composed of alternating positive and negative ions?
Here are the choices:
A. magnetic crystals
B. ionic crystals
C. polar bonds
D. radioactive substances | Ionic crystals are composed of alternating positive and negative ions. | B: ionic crystals. |
What is the term for a small organelle where proteins are made?
Here are the choices:
A. atom
B. ovary
C. ribosome
D. capsule | A ribosome is a small organelle where proteins are made. It’s like a factory in the cell. It gathers amino acids and joins them together into proteins. Unlike other organelles, the ribosome is not surrounded by a membrane. As a result, some scientists do not classify it as an organelle. Ribosomes may be found floating in the cytoplasm. Some ribosomes are located on the surface of another organelle, the endoplasmic reticulum. | C: ribosome. |
What occurs when the immune system attacks harmless substances that enter the body from the outside?
Here are the choices:
A. mutation
B. allergies
C. anomalies
D. cell rejection | Allergies occur when the immune system attacks harmless substances that enter the body from the outside. | B: allergies. |
What is composed of very long strands of glucose monomers, is largely indigestible and comprises the cell walls of plants?
Here are the choices:
A. chlorophyll
B. vascular cambrium
C. tree bark
D. cellulose | Cellulose is composed of very long strands of glucose monomers that are hydrogen bonded to one another. Cellulose is largely indigestible and comprises the cell walls of plants. | D: cellulose. |
Where are the terrestrial planets located, in relation to the sun?
Here are the choices:
A. To the left
B. farthest
C. closest
D. To the right | The four planets closest to the Sun—Mercury, Venus, Earth, and Mars—are the inner planets or terrestrial planets ( Figure below ). They are similar to Earth. All are solid, dense, and rocky. None of the inner planets has rings. Compared to the outer planets, the inner planets are small. They have shorter orbits around the Sun and they spin more slowly. Venus spins backward and spins the slowest of all the planets. | C: closest. |
What are the insects that suck up the sap from plants?
Here are the choices:
A. butterflies and leafhoppers
B. aphids and leafhoppers
C. plagues and leafhoppers
D. roaches and leafhoppers | Insects eat in many different ways and they eat a huge range of foods. Around half are plant-eaters, feeding on leaves, roots, seeds, nectar, or wood. Aphids and leafhoppers suck up the sap from plants. Praying mantises are predators, hunting other small creatures, including insects like moths, caterpillars, flies, beetles, and spiders. Insects like mosquitoes and aphids have special mouthparts that help them pierce and suck. Others, like assassin bugs ( Figure below ) and certain species of female mosquitoes, eat other insects. Fleas and lice are parasites, eating the flesh or blood of larger animals without killing them. | B: aphids and leafhoppers. |
The energy for an ecosystem can come from sunlight or _________?
Here are the choices:
A. chemical compounds
B. radiation compounds
C. fossil fuels
D. rain | All ecosystems need a constant input of energy in the form of sunlight or chemical compounds. Living things can be classified based on how they obtain energy as producers, consumers, or decomposers. | A: chemical compounds. |
Phagocytosis, pinocytosis, and receptor-mediated endocytosis are the three types of what?
Here are the choices:
A. nanoparticles
B. endocytosis
C. mitosis
D. modulators | B: endocytosis. | |
What type of machines generally have lower efficiency but greater mechanical advantage?
Here are the choices:
A. simple machines
B. radical machines
C. compound machines
D. calculation machines | Compound machines generally have lower efficiency but greater mechanical advantage than simple machines. | C: compound machines. |
What is the name of the layer above the mesosphere?
Here are the choices:
A. lithosphere
B. thermosphere
C. exosphere
D. intersphere | The thermosphere is the layer above the mesosphere. It rises to 600 kilometers (372 miles) above the surface. The International Space Station and other space stations orbit Earth in this layer. | B: thermosphere. |
What layer of earth contains abundant oxygen, which can combine with other elements to create oxide minerals?
Here are the choices:
A. the surface
B. the tectonic plates
C. the crust
D. the core | Earth’s crust contains a lot of oxygen. The oxygen can combine with other elements to create oxide minerals. Oxides contain one or two metal elements combined with oxygen. Oxides are different from silicates, because they do not contain silicon. Many important metals are found as oxides. For example, hematite and magnetite are both oxides that contain iron. Hematite (Fe 2 O 3 ) has a ratio of two iron atoms to three oxygen atoms. Magnetite (Fe 3 O 4 ) has a ratio of three iron atoms to four oxygen atoms. Notice that the word “magnetite” contains the word “magnet. " Magnetite ( Figure below ) is a magnetic mineral. | C: the crust. |
Animals that are endotherms or ectotherms are distinguished by the ability to maintain a constant what?
Here are the choices:
A. body temperature
B. bearing temperature
C. step temperature
D. Moving Tempature | Endotherms and Ectotherms Animals can be divided into two groups: some maintain a constant body temperature in the face of differing environmental temperatures, while others have a body temperature that is the same as their environment and thus varies with the environment. Animals that do not control their body temperature are ectotherms. This group has been called cold-blooded, but the term may not apply to an animal in the desert with a very warm body temperature. In contrast to ectotherms, which rely on external temperatures to set their body temperatures, poikilotherms are animals with constantly varying internal temperatures. An animal that maintains a constant body temperature in the face of environmental changes is called a homeotherm. Endotherms are animals that rely on internal sources for body temperature but which can exhibit extremes in temperature. These animals are able to maintain a level of activity at cooler temperature, which an ectotherm cannot due to differing enzyme levels of activity. | A: body temperature. |
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