questions stringlengths 37 1.22k | reasoning stringlengths 0 3.56k ⌀ | answers stringlengths 4 138 |
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What type of energy is required in all chemical reactions?
Here are the choices:
A. solar
B. activation
C. conduction
D. function | All chemical reactions require activation energy, which is the energy needed to get a reaction started. | B: activation. |
What type of image is formed when light rays diverge in front of a mirror?
Here are the choices:
A. large
B. reversed
C. virtual
D. fake | When light rays diverge in front of a mirror, a virtual image is formed. A virtual image is formed by your brain tracing diverging rays backwards and is kind of a trick, like the person you see “behind” a mirror’s surface when you brush your teeth (there's obviously no real light focused behind a mirror!). Since virtua... | C: virtual. |
What is the condition of a plant in which the fluid in a cell exerts a pressure against the cell wall?
Here are the choices:
A. hydration
B. constriction
C. turgor
D. tumor | called the relative osmotic pressure if neither solution is pure water, and it is called the osmotic pressure if one solution is pure water. Osmotic pressure can be large, depending on the size of the concentration difference. For example, if pure water and sea water are separated by a semipermeable membrane that passe... | C: turgor. |
What phenomenon, crucial for evolution, creates new genetic variation in a gene pool and is how all new alleles first arise?
Here are the choices:
A. radiation
B. adaptation
C. mutation
D. natural selection | Mutation creates new genetic variation in a gene pool. It is how all new alleles first arise. In sexually reproducing species, the mutations that matter for evolution are those that occur in gametes. Only these mutations can be passed to offspring. For any given gene, the chance of a mutation occurring in a given gamet... | C: mutation. |
What is the name of the stage of life when a child becomes sexually mature?
Here are the choices:
A. reproductive stage
B. puberty
C. pre-adolescence
D. adulthood | Puberty is the stage of life when a child becomes sexually mature. Puberty begins when the pituitary gland tells the testes to secrete testosterone in boys, and in girls the pituitary gland signals the ovaries to secrete estrogen. Changes that occur during puberty are discussed in the Male Reproductive Development and ... | B: puberty. |
A man made lake is known as what?
Here are the choices:
A. Lake
B. Lagoon
C. Pond
D. resevoirs | Many lakes are not natural, but are human-made. People dam a stream in a suitable spot. Water backs up behind the dam, creating a lake. These lakes are "reservoirs" ( Figure below ). | D: resevoirs. |
Alchemy helped improve the study of metallurgy and the extraction of metals from what?
Here are the choices:
A. wood
B. water
C. air
D. ores | However, out of all this secrecy came several contributions to modern-day chemistry. Early acids and bases were discovered. Glassware for running chemical reactions was developed. Alchemy helped improve the study of metallurgy and the extraction of metals from ores. More systematic approaches to research were being dev... | D: ores. |
What are the two types of vascular tissues?
Here are the choices:
A. ganglia and phloem
B. xylem and phloem
C. ectoderm and phloem
D. epidermis and phloem | Vascular tissue runs through the ground tissue inside a plant. It transports fluids throughout the plant. Vascular tissue actually consists of two types of tissues, called xylem and phloem. The two types of vascular tissue are packaged together in bundles. You can see them in the celery in Figure below . | B: xylem and phloem. |
The spinal cord develops, cells making up the wall of the neural tube proliferate and differentiate into what?
Here are the choices:
A. jelly and glia
B. neurons and glia
C. muscles and glia
D. membrane and glia | Spinal Cord Development While the brain is developing from the anterior neural tube, the spinal cord is developing from the posterior neural tube. However, its structure does not differ from the basic layout of the neural tube. It is a long, straight cord with a small, hollow space down the center. The neural tube is d... | B: neurons and glia. |
Eventually the parent cell will pinch apart to form two identical types of what cells?
Here are the choices:
A. father cells
B. son cells
C. daughter cells
D. brother cells | Cell division is relatively simple in prokaryotic cells. The two cells divide by binary fission. Green and orange lines indicate old and newly-generated bacterial cell walls, respectively. Eventually the parent cell will pinch apart to form two identical daughter cells. Left, growth at the center of bacterial body, suc... | C: daughter cells. |
The body cells cannot use insulin properly in which type of diabetes?
Here are the choices:
A. type 3 diabates
B. type 2 diabetes
C. type 1 diabetes
D. type 4 diabetes | In type 2 diabetes, the body cells cannot use insulin properly. | B: type 2 diabetes. |
Birds belong to a group of diapsids called the what?
Here are the choices:
A. conifers
B. mammals
C. archosaurs
D. aviators | Evolution of Birds The evolutionary history of birds is still somewhat unclear. Due to the fragility of bird bones, they do not fossilize as well as other vertebrates. Birds are diapsids, meaning they have two fenestrations or openings in their skulls. Birds belong to a group of diapsids called the archosaurs, which al... | C: archosaurs. |
How many limbs to birds have?
Here are the choices:
A. six
B. four
C. ten
D. five | Birds are four-limbed, endothermic vertebrates with wings and feathers. They produce amniotic eggs and are the most numerous class of vertebrates. | B: four. |
Planes fly in what layer of the atmosphere because there is less friction and turbulence?
Here are the choices:
A. stratosphere
B. mesosphere
C. ozone layer
D. crust | Sure we can! If you've ever flown on a jet airplane, you've been in the stratosphere. Airplanes fly in the stratosphere, because there is less friction. They get better gas mileage and so costs are lower. There is also less turbulence, so passengers are happier. Can you identify the bottom of the stratosphere in the ph... | A: stratosphere. |
What is a group of similar ecosystems with the same general abiotic factors and primary producers?
Here are the choices:
A. family
B. biome
C. ecoregion
D. taxon | The two photos in Figure above represent two different biomes. A biome is a group of similar ecosystems with the same general abiotic factors and primary producers. Producers are organisms that produce food for themselves and other organisms. Biomes may be terrestrial or aquatic. | B: biome. |
Interferons are produced in virally infected cells and cause them to secrete signals for surrounding cells to make what?
Here are the choices:
A. resist proteins
B. antiviral proteins
C. Raising Proteins
D. overwhelm proteins | Chapter 21 1 The three main components are the lymph vessels, the lymph nodes, and the lymph. 3 The bacterium is digested by the phagocyte’s digestive enzymes (contained in its lysosomes). 5 B 7 C 9 A 11 D 13 C 15 B 17 B 19 D 21 D 23 B 25 C 27 B 29 C 31 D 33 A 35 B 37 B 39 The lymph enters through lymphatic capillaries... | B: antiviral proteins. |
What slow process is required for formation of soil?
Here are the choices:
A. digestion
B. weathering
C. leaching
D. fossilization | Soil formation requires weathering. Where there is less weathering, soils are thinner. However, soluble minerals may be present. Where there is intense weathering, soils may be thick. Minerals and nutrients would have been washed out. Soil development takes a very long time. It may take hundreds or even thousands of ye... | B: weathering. |
What is defined as superheated gas with a positive electrical charge?
Here are the choices:
A. ion
B. plasma
C. greenhouse gas
D. supernova | The Sun is made mostly of plasma. Plasma is superheated gas with a positive electrical charge. | B: plasma. |
Materials, such as iron, that exhibit strong magnetic effects are labeled what?
Here are the choices:
A. ferromagnetic
B. paramagnetic
C. ultramagnetic
D. superconducting | Magnetic poles always occur in pairs of north and south—it is not possible to isolate north and south poles. All magnetism is created by electric current. Ferromagnetic materials, such as iron, are those that exhibit strong magnetic effects. The atoms in ferromagnetic materials act like small magnets (due to currents w... | A: ferromagnetic. |
Like birds, most other reptiles excrete their nitrogenous wastes as what acid?
Here are the choices:
A. sulphuric
B. uric
C. hydrochloric
D. lactic | B: uric. | |
The two main fundamental particles that make up neutrons are quarks and what else?
Here are the choices:
A. prions
B. leptons
C. gluons
D. atoms | Neutrons consist of fundamental particles known as quarks and gluons. Gluons carry the strong nuclear force that binds together the quarks in a neutron. | C: gluons. |
Birds have evolved a respiratory system that enables them to fly. flying is a high-energy process and requires a lot of this?
Here are the choices:
A. oxygen
B. nitrogen
C. adaptation
D. weight | Avian Respiration Birds have evolved a respiratory system that enables them to fly. Flying is a high-energy process and requires a lot of oxygen. Furthermore, many birds fly in high altitudes where the concentration of oxygen in low. How did birds evolve a respiratory system that is so unique? Decades of research by pa... | A: oxygen. |
Lysosomes have what type of enzymes that break down old molecules into parts that can be recycled?
Here are the choices:
A. bacterial
B. corrosive
C. digestive
D. probiotics | Lysosomes are like the recycling trucks that carry waste away from the factory. Lysosomes have digestive enzymes that break down old molecules into parts that can be recycled. | C: digestive. |
The breasts contain what to give milk to feed a baby?
Here are the choices:
A. sebaceous glands
B. fetal glands
C. primordial glands
D. mammary glands | The female reproductive organs include the vagina, uterus, fallopian tubes, and ovaries ( Figure below ). The breasts are not shown in this figure. They are not considered reproductive organs, even though they are involved in reproduction. They contain mammary glands that give milk to feed a baby. The milk leaves the b... | D: mammary glands. |
What form when water vapor condenses in the air around specs of matter?
Here are the choices:
A. humidity
B. condensation
C. clouds
D. storms | Clouds form when water vapor condenses in the air around specs of matter. Clouds are classified on the basis of where and how they form. Types of clouds include cirrus, stratus, and cumulus clouds. | C: clouds. |
All other forms of life, including plants and animals, are composed of what kind of cells?
Here are the choices:
A. bacterial
B. cytoplasmic
C. synthetic
D. eukaryotic | D: eukaryotic. | |
A mycorrhiza refers to what kind of relationship between a fungus and the roots of a plant?
Here are the choices:
A. symbiotic
B. familial
C. semantic
D. predator-prey | A mycorrhiza (Greek for "fungus roots") is a symbiotic association between a fungus and the roots of a plant. In a mycorrhizal association, the fungus may colonize the roots of a host plant by either growing directly into the root cells, or by growing around the root cells. This association provides the fungus with rel... | A: symbiotic. |
What is earth's main source of energy?
Here are the choices:
A. the core
B. the atmosphere
C. the sun
D. the moon | The Sun is Earth’s main source of energy. The Sun gives us both light and heat. The Sun changes hydrogen into helium through nuclear fusion. This releases huge amounts of energy. The energy travels to the Earth mostly as visible light. The energy is carried through the empty space by radiation . We can use sunlight as ... | C: the sun. |
Kirchhoff’s second rule (the loop rule) is an application of conservation of what?
Here are the choices:
A. Rock
B. energy
C. mineral
D. heating | Kirchhoff’s Second Rule Kirchhoff’s second rule (the loop rule) is an application of conservation of energy. The loop rule is stated in terms of potential, V , rather than potential energy, but the two are related since PE elec = qV . Recall that emf is the potential difference of a source when no current is flowing. I... | B: energy. |
Evolution over a short period of time at the level of the population is called what?
Here are the choices:
A. grammaticalization
B. redistributions
C. macroevolution
D. microevolution | The time scale of evolution can vary. Evolution over a short period of time at the level of the population is called microevolution. Evolution over a long period of time above the level of the species is called macroevolution. | D: microevolution. |
When water is heated by magma and makes it's way to the surface what is created?
Here are the choices:
A. trough
B. geyser
C. eruption
D. volcanic | Water works its way through porous rocks or soil. Sometimes this water is heated by nearby magma. If the water makes its way to the surface, it forms a hot spring or a geyser. | B: geyser. |
The mechanical and digestive processes have one goal: to convert food into molecules small enough to be absorbed by the epithelial cells of what?
Here are the choices:
A. alveoli
B. stomach cilia
C. bile ducts
D. intestinal villi | Absorption The mechanical and digestive processes have one goal: to convert food into molecules small enough to be absorbed by the epithelial cells of the intestinal villi. The absorptive capacity of the alimentary canal is almost endless. Each day, the alimentary canal processes up to 10 liters of food, liquids, and G... | D: intestinal villi. |
Influenza virus is packaged in a viral envelope, which fuses with the what?
Here are the choices:
A. cell wall
B. plasma membrane
C. bacteria
D. nucleus | Influenza virus is packaged in a viral envelope, which fuses with the plasma membrane. This way, the virus can exit the host cell without killing it. What advantage does the virus gain by keeping the host cell alive?. | B: plasma membrane. |
A desert is a type of what community in an ecosystem?
Here are the choices:
A. colony
B. culture
C. population
D. biome | This scene is from Anza-Borrago California Desert Park. However, deserts exist around the globe. You might find a similar picture of a desert in Africa. The desert is one type of biome. | D: biome. |
What are the two types of properties that matter has?
Here are the choices:
A. size and shape
B. nature and purpose
C. composition and weight
D. physical and chemical | Matter has both physical and chemical properties. Physical properties can be measured or observed without matter changing to a different substance. | D: physical and chemical. |
What is the hormone produced in high-stress situations?
Here are the choices:
A. somatostatin
B. thyroxine
C. testosterone
D. adrenalin | In the health sciences, the concentration of a solution is typically expressed asparts per thousand (ppt), indicated as a proportion. For example, adrenalin, the hormone produced in high-stress situations, is available in a 1:1000 solution, or one gram of adrenalin per 1000 g of solution. The labels on bottles of comme... | D: adrenalin. |
What type of reaction causes two substances to combine to make a single substance?
Here are the choices:
A. composition reaction
B. component reaction
C. metabolism
D. spontaneous mutation | In this equation, two substances combine to make a single substance. This is a composition reaction. Two different substances react to make two new substances. This does not fit the definition of either a composition reaction or a decomposition reaction, so it is neither. In fact, you may recognize this as a double-rep... | A: composition reaction. |
Hay fever is actually an allergy to what substance, vital to plant reproduction?
Here are the choices:
A. grass
B. fungi
C. nitrogen
D. pollen | Did you ever hear of hay fever? It’s not really a fever at all. It’s an allergy to plant pollens. People with this type of allergy have symptoms such as watery eyes, sneezing, and a runny nose. A common cause of hay fever is the pollen of ragweed. Many people are also allergic to poison ivy ( Figure below ). Skin conta... | D: pollen. |
Endotherms are warmed mostly by heat generated by what?
Here are the choices:
A. metabolism
B. electricity
C. the sun
D. movement | A: metabolism. | |
If a ball is released from rest when air resistance is negligible, velocity is seen to increase linearly, while what related property is a constant?
Here are the choices:
A. acceleration
B. density
C. time
D. speed | Figure 2.43 Positions and velocities of a metal ball released from rest when air resistance is negligible. Velocity is seen to increase linearly with time while displacement increases with time squared. Acceleration is a constant and is equal to gravitational acceleration. | A: acceleration. |
What term is used to describe the ability of matter to burn?
Here are the choices:
A. permeability
B. flammability
C. volatility
D. reactivity | Flammability is the ability of matter to burn. When matter burns, it combines with oxygen and changes to different substances. Wood is an example of flammable matter, as seen in Figure below . | B: flammability. |
What is the evolutionary history of group of related organisms
Here are the choices:
A. phylogeny
B. history
C. iteration
D. substructure | Phylogeny is the evolutionary history of group of related organisms. It is represented by a phylogenetic tree that shows how species are related to each other through common ancestors. | A: phylogeny. |
What forms a ketone when oxidized?
Here are the choices:
A. enzyme
B. carbolic acid
C. secondary alcohol
D. aldehyde | A secondary alcohol forms a ketone when oxidized. The secondary alcohol cannot be further oxidized to produce a carboxylic acid. Tertiary alcohols cannot be oxidized in this way, because the carbon atom bonded to the OH group is not also bonded to any hydrogens. | C: secondary alcohol. |
What is the energy that flows as a result of a difference in temperature?
Here are the choices:
A. polarity
B. magnetism
C. heat
D. electricity | Heat is the energy that flows as a result of a difference in temperature. We use the symbol for heat. Heat, like all forms of energy, is measured in joules. | C: heat. |
Exposure to toxins is most damaging during weeks 4 through 8 of the embryonic stage due to development of what during this period?
Here are the choices:
A. faith
B. pain
C. organs
D. samples | Embryonic Development (Weeks 4–8). Most organs develop in the embryo during weeks 4 through 8. If the embryo is exposed to toxins during this period, the effects are likely to be very damaging. Can you explain why? (Note: the drawings of the embryos are not to scale. ). | C: organs. |
What evolutionary process may affect the distribution of a polygenic trait?
Here are the choices:
A. natural selection
B. flow selection
C. artificial selection
D. characteristic selection | Natural Selection for a Polygenic Trait. Natural selection may affect the distribution of a polygenic trait. These graphs show three ways this can happen. | A: natural selection. |
What type of force exists between two touching surfaces?
Here are the choices:
A. opposing
B. tension
C. friction
D. centrifugal | Friction is the force that resists motion. In most beginning physics classes, friction is ignored. Concepts can be understood and calculations made assuming friction to be nonexistent. Whenever physics intersects with the real world, however, friction must be taken into account. Friction exists between two touching sur... | C: friction. |
A short reflex is completely what and only involves the local integration of sensory input with motor output?
Here are the choices:
A. neuronal
B. peripheral
C. physiological
D. central | Short and Long Reflexes Somatic reflexes involve sensory neurons that connect sensory receptors to the CNS and motor neurons that project back out to the skeletal muscles. Visceral reflexes that involve the thoracolumbar or craniosacral systems share similar connections. However, there are reflexes that do not need to ... | B: peripheral. |
The urea cycle, a set of biochemical reactions that produces urea from ammonium ions to prevent toxicity, occurs to some extent in the kidney, but primarily in what organ?
Here are the choices:
A. liver
B. skin
C. spleen
D. colon | Urea Cycle The urea cycle is a set of biochemical reactions that produces urea from ammonium ions in order to prevent a toxic level of ammonium in the body. It occurs primarily in the liver and, to a lesser extent, in the kidney. Prior to the urea cycle, ammonium ions are produced from the breakdown of amino acids. In ... | A: liver. |
Cellular respiration is the reverse or opposite of what?
Here are the choices:
A. spermatogenesis
B. photosynthesis
C. glycolysis
D. reproduction | Specifically, during cellular respiration, the energy stored in glucose is transferred to ATP ( Figure below ). ATP , or adenosine triphosphate, is chemical energy the cell can use. It is the molecule that provides energy for your cells to perform work, such as moving your muscles as you walk down the street. But cellu... | B: photosynthesis. |
What force pulls object downwards to the earth?
Here are the choices:
A. momentum
B. gravity
C. motion
D. kinetic energy | Gravity near the Earth pulls an object downwards toward the surface of the Earth with an acceleration of . In the absence of air resistance, all objects will fall with the same acceleration. The letter is used as the symbol for the acceleration of gravity. When talking about an object's acceleration, whether it is due ... | B: gravity. |
How does deeper material cause convection in the mantle?
Here are the choices:
A. rises then sinks
B. folds
C. remains stable
D. sinks then rises | Not long after Wegener's death, scientists recognized that there is convection in the mantle. Deeper material is hotter and so it rises. Near the surface, it becomes cooler and denser so it sinks. This creates a convection cell in the mantle. | A: rises then sinks. |
From what did the first proto-oncogenes arise?
Here are the choices:
A. bacteria
B. carcinogens
C. spores
D. viral infections | D: viral infections. | |
What material used for helium-filled balloons is dense, strong and opaque, with a high molecular mass that forms films that have many fewer pores than rubber?
Here are the choices:
A. fiberglass
B. cellophane
C. mylar
D. foil | times faster than air. For this reason, high-quality helium-filled balloons are usually made of Mylar, a dense, strong, opaque material with a high molecular mass that forms films that have many fewer pores than rubber. Mylar balloons can retain their helium for days. | C: mylar. |
What do erythrocytes carry and deliver to tissues in the body?
Here are the choices:
A. oxide
B. oxygen
C. carbon
D. Helium | The cell found in greatest abundance in blood is the erythrocyte. Erythrocytes are counted in millions in a blood sample: the average number of red blood cells in primates is 4.7 to 5.5 million cells per microliter. Erythrocytes are consistently the same size in a species, but vary in size between species. For example,... | B: oxygen. |
How many neutrons do 99% of carbon atoms have?
Here are the choices:
A. sixteen
B. five
C. eight
D. six | All the atoms of a given element have the same number of protons and electrons. The number of neutrons, however, may vary for atoms of the same element. For example, almost 99 percent of carbon atoms have six neutrons, but the rest have either seven or eight neutrons. Atoms of an element that differ in their numbers of... | D: six. |
What are the two metals within a battery called?
Here are the choices:
A. anode and diode
B. anode and sheath
C. anode and a cathode
D. sheath and a cathode | These values suggest that water should be oxidized at the anode because a smaller potential would be needed—using reaction (ii) for the oxidation would give a less-negative cell potential. When the experiment is run, it turns out chlorine, not oxygen, is produced at the anode. The unexpected process is so common in ele... | C: anode and a cathode. |
What is one thing that can not happen to energy?
Here are the choices:
A. it cannot decrease
B. it cannot stay the same
C. it cannot increase
D. it can not be destroyed | If energy cannot be destroyed, what happens to the energy that is absorbed in an endothermic reaction? The energy is stored in the chemical bonds of the products. This form of energy is called chemical energy. In an endothermic reaction, the products have more stored chemical energy than the reactants. In an exothermic... | D: it can not be destroyed. |
Where do most biochemical reactions take place?
Here are the choices:
A. within cells
B. outside of cells
C. upper atmosphere
D. stomach | Most biochemical reactions take place within cells. Cells are the microscopic building blocks of organisms. | A: within cells. |
The ends of linear chromosomes are maintained by the action of which enzyme?
Here are the choices:
A. cytokine
B. insulin
C. pepsin
D. telomerase | Figure 9.11 The ends of linear chromosomes are maintained by the action of the telomerase enzyme. | D: telomerase. |
Through which process does water from the oceans enter the atmosphere?
Here are the choices:
A. absorption
B. perspiration
C. evaporation
D. oxidation | C: evaporation. | |
In what type of process does heat flow into its surroundings and cause an increase in kinetic energy?
Here are the choices:
A. biochemical process
B. oscillating process
C. chemical process
D. exothermic process | In general, the process of interest is taking place in the system, and there are no changes in the composition of the surroundings. However, the temperature of the surroundings does generally change. Entropy changes in the surroundings are determined primarily by the flow of heat into or out of the system. In an exothe... | D: exothermic process. |
Prokaryotic organisms, like bacteria, reproduce through what process, where they grow and divide in half?
Here are the choices:
A. singular fission
B. symbiotic fission
C. multiple fission
D. binary fission | Prokaryotic organisms, like bacteria. Bacteria reproduce through binary fission , where they grow and divide in half ( Figure below ). First, their chromosome replicates and the cell enlarges. The cell then divides into two cells as new membranes form to separate the two cells. After cell division, the two new cells ea... | D: binary fission. |
Displacement is a vector quantity, which means it has both direction and what else?
Here are the choices:
A. rate
B. radiation
C. waves
D. magnitude | What is the difference between distance and displacement? Whereas displacement is defined by both direction and magnitude, distance is defined only by magnitude. Displacement is an example of a vector quantity. Distance is an example of a scalar quantity. A vector is any quantity with both magnitude and direction. Othe... | D: magnitude. |
Waste leaves the body in the form of what?
Here are the choices:
A. feces
B. saliva
C. impurities
D. stomach acid | A: feces. | |
What process can occur when atoms are exposed to high levels of radiation or when atoms transfer electrons to or from other atoms?
Here are the choices:
A. oxidation
B. ionization
C. diffusion
D. fusion | The process in which an atom becomes an ion is called ionization. It may occur when atoms are exposed to high levels of radiation or when atoms transfer electrons to or from other atoms. | B: ionization. |
Who should an obese person with an eating disorder seek for help?
Here are the choices:
A. social worker
B. health professional
C. body builder
D. psychiatrist | Some people who are obese have an eating disorder. Eating disorders are mental illnesses that require treatment by health professionals. | B: health professional. |
The period of life between the start of puberty and the beginning of adulthood is called?
Here are the choices:
A. youth
B. prenatal
C. old age
D. adolescence | Adolescence is the period of life between the start of puberty and the beginning of adulthood. Adolescence includes the physical changes of puberty. It also includes many other changes, including significant mental, emotional, and social changes. During adolescence:. | D: adolescence. |
What element once commonly used in paint and gasoline has now been found to have dangerous effects?
Here are the choices:
A. chromium
B. plastic
C. niacin
D. lead | lead: An element that was once commonly used in gasoline and paint, is now found to have dangerous effects, such as brain damage. Lead contamination has many harmful effects on the body. | D: lead. |
What can happen spontaneously or as a result of mutagens in the environment?
Here are the choices:
A. mutations
B. lesions
C. combustion
D. traits | Many mutations are not caused by errors in replication. Mutations can happen spontaneously, and they can be caused by mutagens in the environment. Some chemicals, such as those found in tobacco smoke, can be mutagens. Sometimes mutagens can also cause cancer. Tobacco smoke, for example, is often linked to lung cancer. | A: mutations. |
Abnormally high activity or low activity of the parathyroid gland can cause disorders related to levels of what bone mineral?
Here are the choices:
A. potassium
B. collagen
C. calcium
D. magnesium | Abnormally high activity of the parathyroid gland can cause hyperparathyroidism, a disorder caused by an overproduction of PTH that results in excessive calcium reabsorption from bone. Hyperparathyroidism can significantly decrease bone density, leading to spontaneous fractures or deformities. As blood calcium levels r... | C: calcium. |
Unlike other tetrapod vertebrates (reptiles, birds, and mammals), amphibians do not produce what type of eggs?
Here are the choices:
A. epithelial
B. amniotic
C. prokaryotic
D. umbilical | Unlike other tetrapod vertebrates (reptiles, birds, and mammals), amphibians do not produce amniotic eggs. Therefore, they must lay their eggs in water so they won’t dry out. Their eggs are usually covered in a jelly-like substance, like the frog eggs shown in Figure below . The jelly helps keep the eggs moist and offe... | B: amniotic. |
What is the name for an underground layer of rock that is saturated with groundwater?
Here are the choices:
A. aqueous cavity
B. artesian well
C. gradient
D. aquifer | An underground layer of rock that is saturated with groundwater is called an aquifer . A diagram of an aquifer is pictured below ( Figure below ). Aquifers are generally found in porous rock, such as sandstone. Water infiltrates the aquifer from the surface. The water that enters the aquifer is called recharge . | D: aquifer. |
What are prepared by the oxidation of secondary alcohols?
Here are the choices:
A. ions
B. ketones
C. protons
D. more alcohol | The carbonyl group, a carbon-to-oxygen double bond, is the defining feature ofaldehydes and ketones. In aldehydes at least one bond on the carbonyl group is a carbon-to-hydrogen bond; in ketones, both available bonds on the carbonyl carbon atom are carbon-to-carbon bonds. Aldehydes are synthesized by the oxidation of p... | B: ketones. |
Saturated and unsaturated are the two main kinds of what?
Here are the choices:
A. acids
B. polymers
C. fats
D. sugars | There are two main types of fats, saturated and unsaturated. | C: fats. |
Most reptiles lay what kind of eggs?
Here are the choices:
A. amniotic
B. roe
C. umbilical
D. hard-shelled | All reptiles have a cloaca , a single exit and entrance for sperm, eggs, and waste, located at the base of the tail. Most reptiles lay amniotic eggs covered with leathery or hard shell. These eggs can be placed anywhere as they don't have to be in a moist environment, like the eggs of amphibians. However, not all speci... | A: amniotic. |
Sulfur can combine with oxygen to produce what?
Here are the choices:
A. sulfur dioxide
B. sulfur trioxide
C. sulfur oxide
D. sulfur bioxide | When nonmetals react with one another, the product is a molecular compound. Often, the nonmetal reactants can combine in different ratios and produce different products. Sulfur can also combine with oxygen to produce sulfur trioxide. | B: sulfur trioxide. |
The nitrogen that enters living systems by nitrogen fixation is successively converted from organic nitrogen back into nitrogen gas by what?
Here are the choices:
A. viruses
B. algae
C. pollen
D. bacteria | The Nitrogen Cycle Getting nitrogen into the living world is difficult. Plants and phytoplankton are not equipped to incorporate nitrogen from the atmosphere (which exists as tightly bonded, triple covalent N2) even though this molecule comprises approximately 78 percent of the atmosphere. Nitrogen enters the living wo... | D: bacteria. |
What term describes the amount of solute in a given amount of solution?
Here are the choices:
A. density
B. concentration
C. cloudiness
D. temperature | The concentration of a solution is the amount of solute in a given amount of solution. A dilute solution has a low concentration of solute. A concentrated solution has a high concentration of solute. | B: concentration. |
Which process helps absorptive protists absorb food molecules across their cell membranes?
Here are the choices:
A. metabolism
B. activation
C. secretion
D. diffusion | Absorptive protists absorb food molecules across their cell membranes. This occurs by diffusion. These protists are important decomposers. | D: diffusion. |
When matter recycles and changes state what does it gain or lose by doing so?
Here are the choices:
A. density
B. fuel
C. energy
D. volume | Matter can exist in one of several different states, including a gas, liquid, or solid state. States of matter differ in the amount of energy their molecules have. When matter recycles, it changes state by gaining or losing energy. | C: energy. |
Where does oxygen enter the blood?
Here are the choices:
A. in the liver
B. in the heart
C. in the veins
D. in the lungs | D: in the lungs. | |
What kind of compounds change color when bases come into contact with them, so they can be used to detect bases?
Here are the choices:
A. liquid
B. metals
C. indicators
D. parameters | Certain compounds, called indicators, change color when bases come into contact with them, so they can be used to detect bases. An example of an indicator is a compound called litmus. It is placed on small strips of paper that may be red or blue. If you place a few drops of a base on a strip of red litmus paper, the pa... | C: indicators. |
Concentric circles that spread out through the water around the droplets are actually types of what moving through the water?
Here are the choices:
A. waves
B. lines
C. winds
D. troughs | No doubt you’ve seen this happen. Droplets of water fall into a body of water, and concentric circles spread out through the water around the droplets. The concentric circles are waves moving through the water. | A: waves. |
The smallest units of matter that retain the unique properties of an element are known as what?
Here are the choices:
A. neutrons
B. molecules
C. atoms
D. protons | All matter is made of tiny particles. Protons, neutrons, and electrons form atoms that bond together to create molecules. Atoms are the smallest units that have the properties of an element. Molecules are the smallest units of a compound. Chemical bonds hold molecules together. Molecules form the different types of min... | C: atoms. |
What is a process that changes some chemical substances into other chemical substances?
Here are the choices:
A. cellular respiration
B. spontaneous mutation
C. a chemical reaction
D. a bio reaction | A chemical reaction is a process that changes some chemical substances into other chemical substances. The substances that start a chemical reaction are called reactants . The substances that form as a result of a chemical reaction are called products . During the reaction, the reactants are used up to create the produ... | C: a chemical reaction. |
What type of lens and mirrors have a negative focal length?
Here are the choices:
A. diverging
B. converging
C. subverging
D. convexing | The focal length , , of a lens or mirror is the distance from the surface of the lens or mirror to the place where the light is focused. This is called the focal point or focus . For diverging lenses or mirrors, the focal length is negative. | A: diverging. |
What is the formation of organs from the germ layers called?
Here are the choices:
A. synaptogenesis
B. biosynthesis
C. photosynthesis
D. organogenesis | 43.7 Organogenesis and Vertebrate Formation Organogenesis is the formation of organs from the germ layers. Each germ layer gives rise to specific tissue types. The first stage is the formation of the neural system in the ectoderm. The mesoderm gives rise to somites and the notochord. Formation of vertebrate axis is ano... | D: organogenesis. |
What must two nuclei do for fusion to occur?
Here are the choices:
A. explode
B. repel each other
C. melt
D. collide | Two nuclei must collide for fusion to occur. High temperatures are required to give the nuclei enough kinetic energy to overcome the very strong repulsion resulting from their positive charges. A nuclear reactor consists of the following: 1. A nuclear fuel. A fissionable isotope must be present in large enough quantiti... | D: collide. |
What determines the ability of soil particles to bind many nutrients?
Here are the choices:
A. surface pulses
B. surface charges
C. layer charges
D. currents charges | B: surface charges. | |
Enthalpy is a measure of the total energy of what kind of system?
Here are the choices:
A. planetary
B. macroscopic
C. hypodermic
D. thermodynamic | Reactions can proceed by themselves if they are exergonic or exothermic, that is if they release energy. The associated free energy of the reaction is composed of two different thermodynamic quantities, enthalpy and entropy. Enthalpy is a measure of the total energy of a thermodynamic system. The change in enthalpy is ... | D: thermodynamic. |
In eukaryotes, the new mrna is not yet ready for translation. it must go through more processing before it leaves where?
Here are the choices:
A. Electrons
B. molecules
C. nucleus
D. protons | In eukaryotes, the new mRNA is not yet ready for translation. It must go through more processing before it leaves the nucleus. This may include splicing, editing, and polyadenylation. These processes modify the mRNA in various ways. Such modifications allow a single gene to be used to make more than one protein. | C: nucleus. |
What term describes the splitting of the nucleus of an atom into two smaller nuclei?
Here are the choices:
A. atomic reaction
B. critical fission
C. nuclean fusion
D. nuclear fission | Nuclear fission is the splitting of the nucleus of an atom into two smaller nuclei. This type of reaction releases a great deal of energy from a very small amount of matter. It begins when the nucleus of a radioactive atom gains a neutron. | D: nuclear fission. |
What type of contamination causes almost 90% of diarrheal disease worldwide?
Here are the choices:
A. air contamination
B. water supply contamination
C. ground contamination
D. food contamination | Unsafe water supplies have drastic effects on human health. Waterborne diseases are diseases due to microscopic pathogens in fresh water. These diseases can be caused by protozoa, viruses, bacteria, and intestinal parasites. In many parts of the world there are no water treatment plants. If sewage or animal manure gets... | B: water supply contamination. |
Why is respiratory acidosis considered to be problematic?
Here are the choices:
A. excess co2 in blood
B. excess oxygen in blood
C. causes suffocation
D. causes acid stomach | Metabolic acidosis is problematic, as lower-than-normal amounts of bicarbonate are present in the blood. The pCO2 would be normal at first, but if compensation has occurred, it would decrease as the body reestablishes the proper ratio of bicarbonate and carbonic acid/CO2. Respiratory acidosis is problematic, as excess ... | A: excess co2 in blood. |
When light strikes rhodopsin, the g-protein transducin is activated, which in turn activates what?
Here are the choices:
A. hydrolysis
B. photosynthesis
C. phosphodiesterase
D. aldosterone | Figure 36.20 When light strikes rhodopsin, the G-protein transducin is activated, which in turn activates phosphodiesterase. Phosphodiesterase converts cGMP to GMP, thereby closing sodium channels. As a result, the membrane becomes hyperpolarized. The hyperpolarized membrane does not release glutamate to the bipolar ce... | C: phosphodiesterase. |
In what stage of photosynthesis does the calvin cycle occur?
Here are the choices:
A. third
B. fourth
C. first
D. second | The Calvin cycle occurs in the second stage of photosynthesis. This stage takes place in the stroma of the chloroplast. In the Calvin cycle, carbon dioxide is used to produce glucose (sugar) using the energy stored in ATP and NADPH. The energy is released from these molecules when ATP loses phosphate (P i ) to become A... | D: second. |
All of the planets rotate on their axes in the same direction that they move around the sun, except for which one?
Here are the choices:
A. Jupiter
B. venus
C. uranus
D. Saturn | All of the planets rotate on their axes in the same direction that they move around the Sun. Except for Uranus. Uranus is tilted on its side. Its axis is almost parallel to its orbit. So Uranus rolls along like a bowling ball as it revolves around the Sun. How did Uranus get this way? Scientists think that the planet w... | C: uranus. |
What is the process by which organisms change in small ways over time?
Here are the choices:
A. microevolution
B. natural selection
C. spontaneous mutation
D. adaptation | Microevolution is the process by which organisms change in small ways over time. | A: microevolution. |
What regulates the cell cycle only when they are tightly bound to cdks?
Here are the choices:
A. cyclins
B. kinases
C. subclades
D. hormones | Cyclins regulate the cell cycle only when they are tightly bound to Cdks. To be fully active, the Cdk/cyclin complex must also be phosphorylated in specific locations. Like all kinases, Cdks are enzymes (kinases) that phosphorylate other proteins. Phosphorylation activates the protein by changing its shape. The protein... | A: cyclins. |
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