questions stringlengths 37 1.22k | reasoning stringlengths 0 3.56k ⌀ | answers stringlengths 4 138 |
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What is occasional chest pain known as?
Here are the choices:
A. arrhythmia
B. heart murmur
C. angina pectoris
D. cardiac arrest | C: angina pectoris. | |
In the cardiovascular system, where is the ultimate destination of the oxygen-poor blood?
Here are the choices:
A. lung
B. brain
C. heart
D. liver | Systemic circulation is the longer loop of the cardiovascular system. It carries blood between the heart and the rest of the body. Oxygen-rich blood flows from the heart to cells throughout the body. As it passes cells, the blood releases oxygen and absorbs carbon dioxide. Then the oxygen-poor blood returns to the heart. | C: heart. |
What is the study of the energy transformations that occur in a collection of matter?
Here are the choices:
A. kinetics
B. fluctuations
C. thermodynamics
D. geophysics | C: thermodynamics. | |
Love canal was an infamous example of what type of pollution?
Here are the choices:
A. Visual Pollution
B. Land Pollution
C. thermal pollution
D. industrial waste dumping | Disposing of industrial waste is one way that human actions pollute the land. This became clear more than 30 years ago in Love Canal, a neighborhood in Niagara Falls, New York. Love Canal may sound lovely, but it is not. Love Canal was and is a disaster. Love Canal been called one of the worst environmental disasters of all time. | D: industrial waste dumping. |
What is a funnel-shaped cloud of whirling high winds known as?
Here are the choices:
A. tornado
B. volcano
C. tsunami
D. hurricane | Severe thunderstorms have a lot of energy and strong winds. This allows them to produce tornadoes. A tornado is a funnel-shaped cloud of whirling high winds. You can see a tornado in Figure below . The funnel moves along the ground, destroying everything in its path. As it moves it loses energy. Before this happens it may have gone up to 25 kilometers (16 miles). Fortunately, tornadoes are narrow. They may be only 150 meters (500 feet) wide. | A: tornado. |
Why do birds need a light-weight body?
Here are the choices:
A. food shortages
B. water flotation
C. to stay aloft
D. for cooling | Birds need a light-weight body in order to stay aloft. Even so, flying is hard work, and flight muscles need a constant supply of oxygen- and nutrient-rich blood. The organ systems of birds are adapted to meet these needs. | C: to stay aloft. |
Asthma, pneumonia, and emphysema are diseases of what system?
Here are the choices:
A. digestive
B. reproductive
C. respiratory
D. pulmonary | Diseases of the respiratory system include asthma, pneumonia, and emphysema. | C: respiratory. |
The “knee-jerk" motion that people involuntarily perform after being struck in the knee in a certain way is an example of what kind of behavior?
Here are the choices:
A. spasm
B. reflex
C. reaction
D. sensor | Innate Behaviors: Movement and Migration Innate or instinctual behaviors rely on response to stimuli. The simplest example of this is a reflex action, an involuntary and rapid response to stimulus. To test the “knee-jerk” reflex, a doctor taps the patellar tendon below the kneecap with a rubber hammer. The stimulation of the nerves there leads to the reflex of extending the leg at the knee. This is similar to the reaction of someone who touches a hot stove and instinctually pulls his or her hand away. Even humans, with our great capacity to learn, still exhibit a variety of innate behaviors. | B: reflex. |
What are tiny, hair like projections?
Here are the choices:
A. cilia
B. actin
C. fuzz
D. spinicles | Many mucous membranes are also covered with cilia. These are tiny, hair-like projections. Cilia move in waves and sweep mucus and trapped pathogens toward body openings. You can see this in the diagram in Figure below . When you clear your throat or blow your nose, you remove mucus and pathogens from your body. | A: cilia. |
How long does it take for the earth to make a complete rotation of its axis?
Here are the choices:
A. 24.25 hours
B. 24 hours
C. one year
D. one month | B: 24 hours. | |
Glaciers have been melting since what period?
Here are the choices:
A. bronze age
B. industrial age
C. stone age
D. pleistocene ice age | Glaciers and ice sheets are melting. This can be seen clearly in photographs. The glaciers advanced during the Pleistocene ice age. They have been melting back since then, except for during the Little Ice Age. However, the rate of melting has increased tremendously in recent decades. | D: pleistocene ice age. |
The transmission electron micrograph shows the cell walls where two cells do what?
Here are the choices:
A. come together
B. disappear
C. split apart
D. reproduce | A: come together. | |
What form does water take on the planet mars?
Here are the choices:
A. plasma
B. gas
C. liquid
D. ice | Water on Mars can't be a liquid. This is because the pressure of the atmosphere is too low. The planet does have a lot of water; it is in the form of ice. The south pole of Mars has a very visible ice cap. Scientists also have evidence that there is also a lot of ice just under the Martian surface. The ice melts when volcanoes erupt. At this times liquid water flows across the surface. | D: ice. |
The simplest system is that of contractile vacuoles present in what?
Here are the choices:
A. macroorganisms
B. parasites
C. crystals
D. microorganisms | 41.3 Excretion Systems Many systems have evolved for excreting wastes that are simpler than the kidney and urinary systems of vertebrate animals. The simplest system is that of contractile vacuoles present in microorganisms. Flame cells and nephridia in worms perform excretory functions and maintain osmotic balance. Some insects have evolved Malpighian tubules to excrete wastes and maintain osmotic balance. | D: microorganisms. |
Water's very polar compound causes most solutes to do what?
Here are the choices:
A. dissolve
B. gel
C. repel
D. combine | Many solutes dissolve in water because water is a very polar compound. | A: dissolve. |
Which plant group has vascular tissue, seeds, and flowers?
Here are the choices:
A. spores
B. fungi
C. angiosperms
D. microbes | Angiosperms have vascular tissue, seeds, and flowers. | C: angiosperms. |
The point in front of a mirror where the reflected rays intersect is known as what?
Here are the choices:
A. focal point
B. periodic point
C. boundary point
D. reflective point | Some mirrors have a curved rather than flat surface. Curved mirrors can be concave or convex. A concave mirror is shaped like the inside of a bowl. This type of mirror forms either real or virtual images, depending on where the object is placed relative to the focal point. The focal point is the point in front of the mirror where the reflected rays intersect. You can see how concave mirrors form images in Figure below and in the interactive animation at the URL below. The animation allows you to move an object to see how its position affects the image. Concave mirrors are used behind car headlights. They focus the light and make it brighter. They are also used in some telescopes. | A: focal point. |
Any unused energy in food, whether it comes from carbohydrates, proteins, or lipids, is stored in the body where?
Here are the choices:
A. kidneys
B. spleen
C. fat
D. bones | Any unused energy in food, whether it comes from carbohydrates, proteins, or lipids, is stored in the body as fat. An extra 3,500 Calories of energy results in the storage of almost half a kilogram (1 pound) of stored body fat. People who consistently consume more food energy then they need may become obese. Obesity occurs when the body mass index is 30.0 kg/m 2 or greater. Body mass index (BMI) is an estimate of the fat content of the body. It is calculated by dividing a person’s weight (in kilograms) by the square of the person’s height (in meters). Obesity increases the risk of health problems such as type 2 diabetes and hypertension. | C: fat. |
What helps determine the concentration of a species in a solution?
Here are the choices:
A. quantitative analysis
B. qualitative analysis
C. fundamental analysis
D. technical analysis | Summary The concentration of a species in solution can be determined by quantitative analysis. One such method is a titration, in which a measured volume of a solution of one substance, the titrant, is added to a solution of another substance to determine its concentration. The equivalence point in a titration is the point at which exactly enough reactant has been added for the reaction to go to completion. A standard solution, a solution whose concentration is known precisely, is used to determine the concentration of the titrant. Many titrations, especially those that involve acid–base reactions, rely on an indicator. The point at which a color change is observed is the endpoint, which is close to the equivalence point if the indicator is chosen properly. | A: quantitative analysis. |
In order to survive and maintain what state, an organism must quickly adapt to changing environmental conditions?
Here are the choices:
A. homeostasis
B. acclimatization
C. ketosis
D. regulation | In prokaryotes, a combination of activators and repressors determines whether a gene is transcribed. As you know, prokaryotic organisms are fairly simple organisms with much less DNA. Prokaryotic genes are arranged in operons , a region of DNA with a promoter, an operator , and one or more genes that encode proteins needed to perform a certain task. To maintain homeostasis (and survive), the organism must quickly adapt changing environmental conditions. The regulation of transcription plays a key role in this process. | A: homeostasis. |
What crust is thinner and denser than continental crust?
Here are the choices:
A. land
B. asteroid
C. coastal
D. oceanic | Oceanic crust is thinner and denser than continental crust. | D: oceanic. |
What are the antibodies an animal produces after exposure to a microbial antigen?
Here are the choices:
A. monoclonal
B. polyclonal
C. chimeric
D. isolated | B: polyclonal. | |
How does heat travel from the sun to the earth?
Here are the choices:
A. through light waves
B. through sound waves
C. secondary radiation from the sun
D. thermal radiation from the sun | The bonfire from the opening image has a lot of thermal energy. Thermal energy is the total kinetic energy of moving particles of matter, and the transfer of thermal energy is called heat. Thermal energy from the bonfire is transferred to the hands by thermal radiation. Thermal radiation is the transfer of thermal energy by waves that can travel through air or even through empty space, as shown in the Figure below . When the waves of thermal energy reach objects, they transfer the energy to the objects, causing them to warm up. This is how the fire warms the hands of someone sitting near the bonfire. This is also how the sun’s energy reaches Earth and heats its surface. Without the energy radiated from the sun, Earth would be too cold to support life as we know it. | D: thermal radiation from the sun. |
What were the first life forms found on earth similar to?
Here are the choices:
A. viruses
B. ferns
C. bacteria
D. mold | Life on Earth began about 3.5 to 4 billion years ago. The first life forms were single-celled organisms similar to bacteria. The first multicellular organisms did not appear until about 610 million years ago. Many different types of organisms evolved during the next ten million years, in an event called the Cambrian Explosion . This sudden burst of evolution may have been caused by some environmental changes that made the Earth's environment more suitable for a wider variety of life forms. | C: bacteria. |
Steel, bronze, and brass are examples of what?
Here are the choices:
A. oxides
B. alloys
C. compounds
D. chemicals | Pure metals may be less useful than mixtures of metals, called alloys. Examples of alloys include steel, bronze, and brass. | B: alloys. |
A pacemaker uses electrical shocks to stimulate the what to beat properly?
Here are the choices:
A. brain
B. heart
C. liver
D. pancreas | Shock Hazards Electrical currents through people produce tremendously varied effects. An electrical current can be used to block back pain. The possibility of using electrical current to stimulate muscle action in paralyzed limbs, perhaps allowing paraplegics to walk, is under study. TV dramatizations in which electrical shocks are used to bring a heart attack victim out of ventricular fibrillation (a massively irregular, often fatal, beating of the heart) are more than common. Yet most electrical shock fatalities occur because a current put the heart into fibrillation. A pacemaker uses electrical shocks to stimulate the heart to beat properly. Some fatal shocks do not produce burns, but warts can be safely burned off with electric current (though freezing using liquid nitrogen is now more common). Of course, there are consistent explanations for these disparate effects. The major factors upon which the effects of electrical shock depend are 1. The amount of current. | B: heart. |
What is the cloud of brown dust-like power that escapes when a puffball fungus is touched?
Here are the choices:
A. pollon
B. spores
C. ions
D. seeds | This is a "puffball" fungus. At maturity, clouds of a brown dust-like power escape when they are touched. This powdery substance is made up of spores, the reproductive structure of the fungus. | B: spores. |
What are the cone-like structures that contain sporangia called?
Here are the choices:
A. strobili
B. gametes
C. medulla
D. contrail | Leaves, Sporophylls, and Strobili A third innovation marks the seedless vascular plants. Accompanying the prominence of the sporophyte and the development of vascular tissue, the appearance of true leaves improved their photosynthetic efficiency. Leaves capture more sunlight with their increased surface area by employing more chloroplasts to trap light energy and convert it to chemical energy, which is then used to fix atmospheric carbon dioxide into carbohydrates. The carbohydrates are exported to the rest of the plant by the conductive cells of phloem tissue. The existence of two types of morphology suggests that leaves evolved independently in several groups of plants. The first type of leaf is the microphyll, or “little leaf,” which can be dated to 350 million years ago in the late Silurian. A microphyll is small and has a simple vascular system. A single unbranched vein—a bundle of vascular tissue made of xylem and phloem—runs through the center of the leaf. Microphylls may have originated from the flattening of lateral branches, or from sporangia that lost their reproductive capabilities. Microphylls are present in the club mosses and probably preceded the development of megaphylls, or “big leaves”, which are larger leaves with a pattern of branching veins. Megaphylls most likely appeared independently several times during the course of evolution. Their complex networks of veins suggest that several branches may have combined into a flattened organ, with the gaps between the branches being filled with photosynthetic tissue. In addition to photosynthesis, leaves play another role in the life of the plants. Pine cones, mature fronds of ferns, and flowers are all sporophylls—leaves that were modified structurally to bear sporangia. Strobili are cone-like structures that contain sporangia. They are prominent in conifers and are commonly known as pine cones. | A: strobili. |
What are considered to be the smallest particles of matter?
Here are the choices:
A. atoms
B. ions
C. cells
D. molecules | All substances are made of atoms. Atoms are the smallest particles of matter. They cannot be divided into smaller particles, created, or destroyed. | A: atoms. |
The mechanics of dynein-based bending involve a process that resembles what?
Here are the choices:
A. standing
B. running
C. jumping
D. walking | D: walking. | |
What type of creature is a scallop?
Here are the choices:
A. insect
B. algae
C. mollusk
D. vertabrate | Some mollusks, such as oysters and scallops, are important food sources. | C: mollusk. |
The risk of what is raised by overexposure to the sun?
Here are the choices:
A. particle cancer
B. flux cancer
C. brain cancer
D. skin cancer | It might be fun to lay out in the sun like these two girls are doing. But getting too much sun can be very dangerous. Overexposure to sunlight raises your risk for skin cancer. | D: skin cancer. |
Which artery enters the cranium through the carotid canal in the temporal bone?
Here are the choices:
A. venal artery
B. internal carotid artery
C. external carotid
D. atrial artery | The internal carotid artery enters the cranium through the carotid canal in the temporal bone. A second set of vessels that supply the CNS are the vertebral arteries, which are protected as they pass through the neck region by the transverse foramina of the cervical vertebrae. The vertebral arteries enter the cranium through the foramen magnum of the occipital bone. Branches off the left and right vertebral arteries merge into the anterior spinal artery supplying the anterior aspect of the spinal cord, found along the anterior median fissure. The two vertebral arteries then merge into the basilar artery, which gives rise to branches to the brain stem and cerebellum. The left and right internal carotid arteries and branches of the basilar artery all become the circle of Willis, a confluence of arteries that can maintain perfusion of the brain even if narrowing or a blockage limits flow through one part (Figure 13.15). | B: internal carotid artery. |
How are aquatic biomes often classified?
Here are the choices:
A. depth
B. amount of salt
C. amount of life
D. amount of light | Recall that terrestrial biomes are defined by their climate. That's because plants and animals are adapted for certain amounts of temperature and moisture. However, would aquatic biomes be classified in the same way? No, that wouldn't make much sense—all parts of an aquatic environment have plenty of water. Aquatic biomes can be generally classified based on the amount of salt in the water. Freshwater biomes have less than 1% salt and are typical of ponds and lakes, streams and rivers, and wetlands. Marine biomes have more salt and are characteristic of the oceans, coral reefs, and estuaries. | B: amount of salt. |
What is the most abundant type of biological entity on the earth?
Here are the choices:
A. insects
B. reptiles
C. bacteria
D. viruses | Viruses were first described by Dmitri Ivanovsky in 1892. He described a "non-bacterial pathogen" infecting tobacco plants. This was soon followed by the identification of the tobacco mosaic virus by Martinus Beijerinck in 1898. Since then, about 5,000 viruses have been described in detail, although it is believed that there are millions of different types. Viruses are found in almost every ecosystem on Earth, and are the most abundant type of biological entity. Viruses can be classified with a taxonomic structure from order to species. No kingdom classification exists. Viruses, not being made of cells, do not fall into any of the six prokaryotic or eukaryotic kingdoms. | D: viruses. |
What is the most diverse and abundant group of organisms on earth, numbering in the millions of trillions?
Here are the choices:
A. viruses
B. bacteria
C. pests
D. pathogens | Bacteria are the most diverse and abundant group of organisms on Earth. They live in almost all environments. They are found in the ocean, the soil, and the intestines of animals. They are even found in rocks deep below Earth’s surface. Any surface that has not been sterilized is likely to be covered with bacteria. The total number of bacteria in the world is amazing. It’s estimated to be 5 × 10 30 , or five million trillion. You have more bacteria in and on your body than you have body cells!. | B: bacteria. |
What kind of hormones are secreted by organs classified as gonads?
Here are the choices:
A. growth hormones
B. cortisol hormones
C. anterior hormones
D. sex hormones | The gonads secrete sex hormones. The male gonads are called testes. They secrete the male sex hormone testosterone. The female gonads are called ovaries. They secrete the female sex hormone estrogen. Sex hormones are involved in the changes of puberty. They also control the production of gametes by the gonads. | D: sex hormones. |
An oxy-acetylene torch is an effective way to cut what?
Here are the choices:
A. wood
B. plastic
C. coal
D. metal | One of the most effective ways to cut metal is with an oxy-acetylene torch. Very high temperatures are obtained when acetylene burns in oxygen. Mixed 1:1 with oxygen, a temperature of over 3000°C can be achieved. The amount of energy released is high – the net heat of combustion is 1300 kJ/mole. Safety precautions need to be observed since the gas is very explosive. For welding and cutting, the oxy-acetylene torch is one of the best ways to go. | D: metal. |
What are the infoldings of the inner membrane called?
Here are the choices:
A. lineage
B. cristae
C. brickle
D. ceranae | B: cristae. | |
A channel protein is an example of what type of protein?
Here are the choices:
A. choice proteins
B. hemoglobin protein
C. component proteins
D. transport proteins | Facilitated diffusion is the diffusion of solutes through transport proteins in the plasma membrane. Channel proteins, gated channel proteins, and carrier proteins are three types of transport proteins that are involved in facilitated diffusion. | D: transport proteins. |
Eight of the hottest years on record have occurred since what year?
Here are the choices:
A. 1997
B. 1991
C. 1998
D. 2002 | Since the mid 1800s, Earth has warmed up quickly. Look at Figure below . The 14 hottest years on record have all occurred since 1900. Eight of them have occurred since 1998! This is what is usually meant by global warming . | C: 1998. |
Average acceleration is the rate of change of what?
Here are the choices:
A. direction
B. velocity
C. speed
D. displacement | Average acceleration is the rate of change of velocity, or the change in velocity per unit time. | B: velocity. |
What is studied to understand gene expression patterns in cells?
Here are the choices:
A. rna
B. dna
C. protein
D. mutations | RNA is studied to understand gene expression patterns in cells. RNA is naturally very unstable because enzymes that break down RNA are commonly present in nature. Some are even secreted by our own skin and are very difficult to inactivate. Similar to DNA extraction, RNA extraction involves the use of various buffers and enzymes to inactivate other macromolecules and preserve only the RNA. Gel Electrophoresis Because nucleic acids are negatively charged ions at neutral or alkaline pH in an aqueous environment, they can be moved by an electric field. Gel electrophoresis is a technique used to separate charged molecules on the basis of size and charge. The nucleic acids can be separated as whole chromosomes or as fragments. The nucleic acids are loaded into a slot at one end of a gel matrix, an electric current is applied, and negatively charged molecules are pulled toward the opposite end of the gel (the end with the positive electrode). Smaller molecules move through the pores in the gel faster than larger molecules; this difference in the rate of migration separates the fragments on the basis of size. The nucleic acids in a gel matrix are invisible until they are stained with a compound that allows them to be seen, such as a dye. Distinct fragments of nucleic acids appear as bands at specific distances from the top of the gel (the negative electrode end) that are based on their size (Figure 10.3). A mixture of many fragments of varying sizes appear as a long smear, whereas uncut genomic DNA is usually too large to run through the gel and forms a single large band at the top of the gel. | A: rna. |
Ribosomes are produced in the nucleolus, and then transported to the what?
Here are the choices:
A. cytoskeleton
B. cerebellum
C. nucleus
D. cytoplasm | Ribosomes are produced in the nucleolus, and then transported to the cytoplasm. Ribosomes are made of ribosomal proteins, called ribonucleoproteins , and ribosomal RNA (rRNA). Each ribosome has two parts, a large and a small subunit, as shown in Figure below . The subunits are attached to each other. During translation, the smaller subunit binds to the mRNA, while the larger subunit binds to the tRNA with attached amino acids. When a ribosome finishes reading an mRNA molecule, the two ribosomal subunits disassociate. | D: cytoplasm. |
Ecosystem dynamics include more than the flow of energy and recycling of matter. ecosystems are also dynamic because they?
Here are the choices:
A. change through time
B. stay the same
C. never move
D. recreate exactly alike | Ecosystem dynamics include more than the flow of energy and recycling of matter. Ecosystems are also dynamic because they change through time. | A: change through time. |
Muscle contraction requires repeated cycles of binding and what?
Here are the choices:
A. lunging
B. release
C. push
D. twisting | B: release. | |
An important chemical compound, which supplies living things with the energy they need to survive, is composed of carbon, oxygen and atoms of what other element?
Here are the choices:
A. hydrogen
B. magnesium
C. nitrogen
D. calcium | The opening image is a model of an important chemical compound. Without it, living things would not have the energy they need to survive. Compared with most other compounds in living things, molecules of this compound are small and simple. In the model, the gray circles represent carbon atoms, the red circles represent oxygen atoms, and the black circles represent hydrogen atoms. | A: hydrogen. |
What are the glands that secrete milk in a woman's breasts?
Here are the choices:
A. lactic acids
B. primordial glands
C. pituitary glands
D. mammary glands | The breasts are not directly involved in reproduction, but they nourish a baby after birth. Each breast contains mammary glands , which secrete milk. The milk drains into ducts leading to the nipple. A suckling baby squeezes the milk out of the ducts and through the nipple. | D: mammary glands. |
Like a thick cap covering the brain, the dura mater is a tough outer covering. the name comes from the latin for?
Here are the choices:
A. tough mother
B. back mother
C. difficult mother
D. protecting mother | Dura Mater Like a thick cap covering the brain, the dura mater is a tough outer covering. The name comes from the Latin for “tough mother” to represent its physically protective role. It encloses the entire CNS and the major blood vessels that enter the cranium and vertebral cavity. It is directly attached to the inner surface of the bones of the cranium and to the very end of the vertebral cavity. There are infoldings of the dura that fit into large crevasses of the brain. Two infoldings go through the midline separations of the cerebrum and cerebellum; one forms a shelf-like tent between the occipital lobes of the cerebrum and the cerebellum, and the other surrounds the pituitary gland. The dura also surrounds and supports the venous sinuses. | A: tough mother. |
Which organisms get their energy source and carbon source from organic sources?
Here are the choices:
A. sporozoans
B. ectomorphs
C. chemoheterotrophs
D. herbivores | Chemoheterotrophs are organisms that get their energy source and carbon source from organic sources. Chemoheterotrophs must consume organic building blocks that they are unable to make themselves. Most get their energy from organic molecules such as sugars. This nutritional mode is very common among eukaryotes, including humans. | C: chemoheterotrophs. |
What natural disaster is california most linked with?
Here are the choices:
A. earthquakes
B. volcanoes
C. hurricanes
D. fires | Although California is prone to many natural hazards, including volcanic eruptions at Mt. Shasta or Mt. Lassen, and landslides on coastal cliffs, the natural hazard the state is linked with is earthquakes. In this video, the boundaries between three different tectonic plates and the earthquakes that result from their interactions are explored. | A: earthquakes. |
Small crustaceans exchange gases across thin areas of the cuticle; larger species have what to accomplish this?
Here are the choices:
A. pores
B. noses
C. gills
D. lungs | C: gills. | |
The superior vena cava and the inferior vena cava are veins that return blood lacking what to the heart?
Here are the choices:
A. oxygen
B. nitrogen
C. hemoglobin
D. carbon dioxide | The veins that return oxygen-poor blood to the heart are the superior vena cava and the inferior vena cava . The pulmonary veins return oxygen-rich blood from the lungs to the heart. The pulmonary veins are the only veins that carry oxygen-rich blood. | A: oxygen. |
There are only four possible bases that make up each dna nucleotide: adenine, guanine, thymine, and?
Here are the choices:
A. cytosine
B. taurine
C. guarine
D. phenylalanine | The only difference between each nucleotide is the identity of the base. There are only four possible bases that make up each DNA nucleotide: adenine (A), guanine (G), thymine (T), and cytosine (C). | A: cytosine. |
What affects the boiling point of water?
Here are the choices:
A. external pressure
B. latter pressure
C. internal pressure
D. heat source | Boiling points are affected by external pressure. | A: external pressure. |
The average length of a woman’s menstrual cycle is what?
Here are the choices:
A. 5 days
B. 28 days
C. 16 days
D. 19 days | The Menstrual Cycle Now that we have discussed the maturation of the cohort of tertiary follicles in the ovary, the build-up and then shedding of the endometrial lining in the uterus, and the function of the uterine tubes and vagina, we can put everything together to talk about the three phases of the menstrual cycle—the series of changes in which the uterine lining is shed, rebuilds, and prepares for implantation. The timing of the menstrual cycle starts with the first day of menses, referred to as day one of a woman’s period. Cycle length is determined by counting the days between the onset of bleeding in two subsequent cycles. Because the average length of a woman’s menstrual cycle is 28 days, this is the time period used to identify the timing of events in the cycle. However, the length of the menstrual cycle varies among women, and even in the same woman from one cycle to the next, typically from 21 to 32 days. Just as the hormones produced by the granulosa and theca cells of the ovary “drive” the follicular and luteal phases of the ovarian cycle, they also control the three distinct phases of the menstrual cycle. These are the menses phase, the proliferative phase, and the secretory phase. | B: 28 days. |
Water leaves ponds and lakes through evaporation and also as what?
Here are the choices:
A. inflow
B. mid flow
C. outflow
D. influx | Ponds and lakes may get their water from several sources. Some falls directly into them as precipitation. Some enters as runoff and some from streams and rivers. Water leaves ponds and lakes through evaporation and also as outflow. | C: outflow. |
What is a biochemical compound that is a chain of amino acids called?
Here are the choices:
A. DNA
B. hormones
C. proteins
D. lipids | Proteins are biochemical compounds that consist of one or more chains of amino acids. Proteins have many different functions. For example, some are enzymes, and some are hormones. | C: proteins. |
Each what is made of two identical sister chromatids?
Here are the choices:
A. genome
B. gene
C. chromosome
D. helix | Chromosomes, like those shown here, must form prior to cell division, to ensure that each daughter cell receives a complete set of genetic material. Each chromosome is made of two identical sister chromatids. Each chromatid is 1/2 of the "X. " Essentially, each daughter cell receives half of each "X-shaped" chromosome. | C: chromosome. |
Amino groups are found within amino acids, nicknamed the building blocks of what?
Here are the choices:
A. carbohydrates
B. lipids
C. protons
D. proteins | Amino groups are found within amino acids, the building blocks of proteins. | D: proteins. |
What is the name of earth’s only natural satellite?
Here are the choices:
A. sun
B. titan
C. venus
D. moon | The Moon is Earth’s only natural satellite. The Moon is about one-fourth the size of Earth, 3,476 kilometers in diameter. Gravity on the Moon is only one-sixth as strong as it is on Earth. If you weigh 120 pounds on Earth, you would only weigh 20 pounds on the Moon. You can jump six times as high on the Moon as you can on Earth. The Moon makes no light of its own. Like every other body in the solar system, it only reflects light from the Sun. | D: moon. |
Which is the lightest of the widely used structural metals?
Here are the choices:
A. Metal
B. magnesium
C. calcium
D. potassium | low, the two metals with the highest ionization energies (beryllium and magnesium) do form compounds that exhibit some covalent characters. Like the alkali metals, the heavier alkaline earth metals impart color to a flame. As in the case of the alkali metals, this is part of the emission spectrum of these elements. Calcium and strontium produce shades of red, whereas barium produces a green color. Magnesium is a silver-white metal that is malleable and ductile at high temperatures. Passivation decreases the reactivity of magnesium metal. Upon exposure to air, a tightly adhering layer of magnesium oxycarbonate forms on the surface of the metal and inhibits further reaction. (The carbonate comes from the reaction of carbon dioxide in the atmosphere. ) Magnesium is the lightest of the widely used structural metals, which is why most magnesium production is for lightweight alloys. Magnesium (shown in Figure 18.6), calcium, strontium, and barium react with water and air. At room temperature, barium shows the most vigorous reaction. The products of the reaction with water are hydrogen and the metal hydroxide. The formation of hydrogen gas indicates that the heavier alkaline earth metals are better reducing agents (more easily oxidized) than is hydrogen. As expected, these metals react with both acids and nonmetals to form ionic compounds. Unlike most salts of the alkali metals, many of the common salts of the alkaline earth metals are insoluble in water because of the high lattice energies of these compounds, containing a divalent metal ion. | B: magnesium. |
When lava flows over a large area and cools, it creates a large, flat surface of what type of rock?
Here are the choices:
A. tidal
B. igneous
C. sedimentary
D. metamorphic | A lava plateau is made of a large amount of fluid lava. The lava flows over a large area and cools. This creates a large, flat surface of igneous rock. Lava plateaus may be huge. The Columbia Plateau covers over 161,000 square kilometers (63,000 square miles). It makes up parts of the states of Washington, Oregon, and Idaho. | B: igneous. |
Examples of what process are evident in many biological systems because cells are surrounded by semipermeable membranes?
Here are the choices:
A. photosynthesis
B. apoptosis
C. osmosis
D. reproduction | Examples of osmosis are evident in many biological systems because cells are surrounded by semipermeable membranes. Carrots and celery that have become limp because they have lost water can be made crisp again by placing them in water. Water moves into the carrot or celery cells by osmosis. A cucumber placed in a concentrated salt solution loses water by osmosis and absorbs some salt to become a pickle. Osmosis can also affect animal cells. Solute concentrations are particularly important when solutions are injected into the body. Solutes in body cell fluids and blood serum give these solutions an osmotic pressure of approximately 7.7 atm. Solutions injected into the body must have the same osmotic pressure as blood serum; that is, they should be isotonic with blood serum. If a less concentrated solution, a hypotonic solution, is injected in sufficient quantity to dilute the blood serum, water from the diluted serum passes into the blood cells by osmosis, causing the cells to expand and rupture. This process is called hemolysis. When a more concentrated solution, a hypertonic solution, is injected, the cells lose water to the more concentrated solution, shrivel, and possibly die in a process called crenation. These effects are illustrated in Figure 11.28. | C: osmosis. |
What does cartilage lack compared to bones, making it softer and less rigid?
Here are the choices:
A. protein
B. calcium
C. potassium
D. magnesium | Skeletons made of cartilage rather than bone. Cartilage is supportive tissue that does not have as much calcium as bones, which makes bones rigid. Cartilage is softer and more flexible than bone. | B: calcium. |
What three forms does frozen precipitation take?
Here are the choices:
A. blizzard, frost, fog
B. snow, sleet, freezing rain
C. hail, wind, typhoon
D. vapor, fog, ice | Frozen precipitation may fall as snow, sleet, or freezing rain. | B: snow, sleet, freezing rain. |
What is a stream of moving water that flows through the ocean?
Here are the choices:
A. creek
B. waterfall
C. current
D. tidal wave | Another way ocean water moves is in currents. A current is a stream of moving water that flows through the ocean. Surface currents are caused mainly by winds, but not the winds that blow and change each day. Surface currents are caused by the major wind belts that blow in the same direction all the time. | C: current. |
The elbow is an example of a what type of joint?
Here are the choices:
A. hinge joint
B. toe joint
C. pipe joint
D. frame joint | Hinge Joints In hinge joints, the slightly rounded end of one bone fits into the slightly hollow end of the other bone. In this way, one bone moves while the other remains stationary, like the hinge of a door. The elbow is an example of a hinge joint. The knee is sometimes classified as a modified hinge joint (Figure 38.28). | A: hinge joint. |
The first leaves of most ferns appear curled up into what?
Here are the choices:
A. fiddleheads
B. petals
C. volatiles
D. nanotubes | The first leaves of most ferns appear curled up into fiddleheads. | A: fiddleheads. |
Electrophiles have a strong tendency to react with what?
Here are the choices:
A. nucleophiles
B. neutrons
C. acids
D. resistors | Electrophiles have a strong tendency to react with nucleophiles. CONCEPTUAL PROBLEMS. | A: nucleophiles. |
What layered form of carbon is used as a lubricant and in pencils?
Here are the choices:
A. lead
B. carbonite
C. graphite
D. copper | Graphite is a form of carbon in which carbon atoms are arranged in layers. Bonds are strong between carbon atoms within each layer but relatively weak between atoms in different layers. The weak bonds between layers allow the layers to slide over one another. This makes graphite relatively soft and slippery. It is used as a lubricant. It also makes up the "lead" in pencils. | C: graphite. |
What kind of solids have particles that are arranged in a regular repeating pattern?
Here are the choices:
A. metabolic solids
B. carbon-based solids
C. salts
D. crystalline solids | Crystalline solids have particles that are arranged in a regular repeating pattern. They form crystals. Amorphous solids have particles that are arranged more-or-less at random. They do not form crystals. | D: crystalline solids. |
During what in the small intestine do rings of smooth muscle repeatedly contract and then relax?
Here are the choices:
A. mitosis
B. segmentation
C. compression
D. contraction | Mechanical Digestion in the Small Intestine The movement of intestinal smooth muscles includes both segmentation and a form of peristalsis called migrating motility complexes. The kind of peristaltic mixing waves seen in the stomach are not observed here. If you could see into the small intestine when it was going through segmentation, it would look as if the contents were being shoved incrementally back and forth, as the rings of smooth muscle repeatedly contract and then relax. Segmentation in the small intestine does not force chyme through the tract. Instead, it combines the chyme with digestive juices and pushes food particles against the mucosa to be absorbed. The duodenum is where the most rapid segmentation occurs, at a rate of about 12 times per minute. In the ileum, segmentations are only about eight times per minute (Figure 23.20). | B: segmentation. |
Acetyl-coa is formed from the breakdown of carbohydrates, lipids, and what else?
Here are the choices:
A. acids
B. hydrocarbons
C. hormones
D. proteins | Acetyl-CoA is formed from the breakdown of carbohydrates, lipids, and proteins. It is used in many biochemical pathways. | D: proteins. |
Juvenile hormone modulates the activity of what?
Here are the choices:
A. reproduction
B. ecdysteroid
C. growth
D. estrogen | B: ecdysteroid. | |
What causes the red color of laterite soils?
Here are the choices:
A. oxygen
B. iron oxides
C. erosion
D. toxins | A third important type of soil is laterite . Laterite forms in tropical areas. Temperatures are warm and rain falls every day ( Figure below ). So much rain falls that chemical weathering is intense. All soluble minerals are washed from the soil. Plant nutrients get carried away. There is practically no humus. Laterite soils are often red in color from the iron oxides. If laterites are exposed to the Sun, they bake as hard as a brick. | B: iron oxides. |
The scientific process of collecting data outside the lab (in the "wild") is known as what kind of work?
Here are the choices:
A. track work
B. field work
C. experimentation
D. scientific investigation | Many Earth scientists collect data in the field, called field work . The data may be from observations or measurements. The scientists may create a geological map of the area. They might write detailed descriptions of the rocks and their relationships. They may collect samples to analyze in the lab. They may do a combination of all of these! Earth science laboratories contain high-tech equipment. That equipment can reveal the chemistry or age of a rock sample. Geologists do field work to look for resources. They may study a region for environmental cleanup. There are many other reasons for going in the field. One common reason is just to understand the region better. | B: field work. |
Red blood cells, white blood cells, platelets, and plasma are all components of what fluid?
Here are the choices:
A. Vessals
B. blood
C. brain
D. heart | 40.2 Components of the Blood Specific components of the blood include red blood cells, white blood cells, platelets, and the plasma, which contains coagulation factors and serum. Blood is important for regulation of the body’s pH, temperature, osmotic pressure, the circulation of nutrients and removal of waste, the distribution of hormones from endocrine glands, and the elimination of excess heat; it also contains components for blood clotting. Red blood cells are specialized cells that contain hemoglobin and circulate through the body delivering oxygen to cells. White blood cells are involved in the immune response to identify and target invading bacteria, viruses, and other foreign organisms; they also recycle waste components, such as old red blood cells. Platelets and blood clotting factors cause the change of the soluble protein fibrinogen to the insoluble protein fibrin at a wound site forming a plug. Plasma consists of 90 percent water along with various substances, such as coagulation factors and antibodies. The serum is the plasma component of the blood without the coagulation factors. | B: blood. |
Who created the idea of an evolutionary tree to represent the relationships between different species and their common ancestors?
Here are the choices:
A. charles darwin
B. Carl Sagan
C. Isaac Newton
D. Scopes | If evolution can take a very long time, how can we visualize how it happens? Charles Darwin came up with the idea of an evolutionary tree to represent the relationships between different species and their common ancestors ( Figure below ). The base of the tree represents the ancient ancestors of all life. The separation into large branches shows where these original species evolved into new species. | A: charles darwin. |
What organs absorb water and nutrients from the soil?
Here are the choices:
A. roots
B. buds
C. leaves
D. flowers | A: roots. | |
What does magma that cools underground form?
Here are the choices:
A. fluctuations
B. new crust
C. chambers
D. instrusions | Magma that cools underground forms intrusions ( Figure below ). Intrusions become land formations if they are exposed at the surface by erosion. | D: instrusions. |
Which season is moist, causing the most thunderstorms?
Here are the choices:
A. spring
B. winter
C. summer
D. autumn | C: summer. | |
What are the two hormones primarily responsible for maintaining homeostasis of blood glucose levels?
Here are the choices:
A. insulin and estrogen
B. insulin and glucagon
C. anabolic and metabolic
D. dopamine and melanin | Hormonal Regulation of Metabolism Blood glucose levels vary widely over the course of a day as periods of food consumption alternate with periods of fasting. Insulin and glucagon are the two hormones primarily responsible for maintaining homeostasis of blood glucose levels. Additional regulation is mediated by the thyroid hormones. | B: insulin and glucagon. |
What important process takes place in specialized tissue inside plant leaves?
Here are the choices:
A. photosynthesis
B. mitosis
C. reproduction
D. pollination | specialized tissue inside plant leaves where photosynthesis takes place. | A: photosynthesis. |
What type of plants were the first to evolve?
Here are the choices:
A. cocklebur
B. nonvascular
C. kilocalorie
D. vascular | Nonvascular plants were the first plants to evolve. Compared to other plants, their small size and lack of specialized structures, such as vascular tissue, stems, leaves, or flowers, explains why these plants evolved first. The first nonvascular plants to evolve were the liverworts. The hornworts evolved somewhat later, and mosses apparently evolved last. Of all the bryophytes, mosses are most similar to vascular plants. Presumably, they share the most recent common ancestor with vascular plants. | B: nonvascular. |
In multicellular organisms, specialized cells may be organized into what, which in turn may be organized into organs?
Here are the choices:
A. blood cells
B. nutrients
C. tissues
D. muscles | In multicellular organisms, specialized cells may be organized into tissues. Tissues may be organized into organs, and organs may be organized into organ systems. Organ systems work together to carry out all the functions of the whole organism. | C: tissues. |
What are accessory digestive organs critical for breaking down?
Here are the choices:
A. enzymes
B. hormones
C. food
D. pathogens | Digestive System Organs The easiest way to understand the digestive system is to divide its organs into two main categories. The first group is the organs that make up the alimentary canal. Accessory digestive organs comprise the second group and are critical for orchestrating the breakdown of food and the assimilation of its nutrients into the body. Accessory digestive organs, despite their name, are critical to the function of the digestive system. | C: food. |
The direction of prevailing winds determines the type of what that usually moves over an area?
Here are the choices:
A. water mass
B. storm
C. weather
D. air mass | The direction of prevailing winds determines which type of air mass usually moves over an area. For example, a west wind might bring warm moist air from over an ocean. An east wind might bring cold dry air from over a mountain range. Which wind prevails has a big effect on the climate. What if the prevailing winds are westerlies? The westerlies blow from nearer the Equator to farther from the Equator. How would they affect the climate?. | D: air mass. |
As blood glucose levels rise what is released from the pancreas?
Here are the choices:
A. insulin
B. estrogen
C. hemoglobin
D. adrenaline | 24.5 Metabolic States of the Body There are three main metabolic states of the body: absorptive (fed), postabsorptive (fasting), and starvation. During any given day, your metabolism switches between absorptive and postabsorptive states. Starvation states happen very rarely in generally well-nourished individuals. When the body is fed, glucose, fats, and proteins are absorbed across the intestinal membrane and enter the bloodstream and lymphatic system to be used immediately for fuel. Any excess is stored for later fasting stages. As blood glucose levels rise, the pancreas releases insulin to stimulate the uptake of glucose by hepatocytes in the liver, muscle cells/fibers, and adipocytes (fat cells), and to promote its conversion to glycogen. As the postabsorptive state begins, glucose levels drop, and there is a corresponding drop in insulin levels. Falling glucose levels trigger the pancreas to release glucagon to turn off glycogen synthesis in the liver and stimulate its breakdown into glucose. The glucose is released into the bloodstream to serve as a fuel source for cells throughout the body. If glycogen stores are depleted during fasting, alternative sources, including fatty acids and proteins, can be metabolized and used as fuel. When the body once again enters the absorptive state after fasting, fats and proteins are digested and used to replenish fat. | A: insulin. |
Hydrocarbons are combined with oxygen in a series of enzymatic steps to product water, carbon dioxide, and energy, which is stored in the form of what?
Here are the choices:
A. light
B. energy
C. reactive molecules
D. dormant molecules | The process of cellular respiration can be thought of as a highly controlled version of a combustion reaction. We do not literally burn hydrocarbons in our body, but the overall reactants and products are the same. Hydrocarbons, such as sucrose (C 12 H 22 O 11 ), are combined with oxygen in a series of enzymatic steps to product water, carbon dioxide, and energy, which is stored in the form of reactive molecules. The unbalanced chemical equation for this overall process is shown below:. | C: reactive molecules. |
The validity of thought experiments, of course, is determined by this?
Here are the choices:
A. actual observation
B. predictive observation
C. hypothetical observation
D. theoretical observation | Now consider what observer B sees happen to observer A. Observer B perceives light from the right reaching observer A before light from the left, because she has moved towards that flash lamp, lessening the distance the light must travel and reducing the time it takes to get to her. Light travels at speed c relative to both observers, but observer B remains equidistant between the points where the flashes were emitted, while A gets closer to the emission point on the right. From observer B’s point of view, then, there is a time interval between the arrival of the flashes to observer A. From observer B’s point of view, then, there is a time interval between the arrival of the flashes to observer A. In observer A's frame of reference, the flashes occur at different times. Observer B measures the flashes to arrive simultaneously relative to him but not relative to A. Now consider what observer A sees happening. She sees the light from the right arriving before light from the left. Since both lamps are the same distance from her in her reference frame, from her perspective, the right flash occurred before the left flash. Here a relative velocity between observers affects whether two events are observed to be simultaneous. Simultaneity is not absolute This illustrates the power of clear thinking. We might have guessed incorrectly that if light is emitted simultaneously, then two observers halfway between the sources would see the flashes simultaneously. But careful analysis shows this not to be the case. Einstein was brilliant at this type of thought experiment (in German, “Gedankenexperiment”). He very carefully considered how an observation is made and disregarded what might seem obvious. The validity of thought experiments, of course, is determined by actual observation. The genius of Einstein is evidenced by the fact that experiments have repeatedly confirmed his theory of relativity. In summary: Two events are defined to be simultaneous if an observer measures them as occurring at the same time (such as by receiving light from the events). Two events are not necessarily simultaneous to all observers. | A: actual observation. |
What do you call a close relationship between two species that benefits both?
Here are the choices:
A. commensalism
B. symbiotic relationship
C. primordial relationship
D. parasitic relationship | Many fungi get organic compounds from living organisms. They have close relationships with other species. A close relationship between two species is called a symbiotic relationship. Two symbiotic relationships in fungi are mycorrhiza and lichen. These relationships are beneficial for both species. | B: symbiotic relationship. |
Generators convert mechanical energy to which kind?
Here are the choices:
A. electrical
B. static
C. kinetic
D. radiation | Generators and motors are almost identical in construction but convert energy in opposite directions. Generators convert mechanical energy to electrical energy and motors convert electrical energy to mechanical. | A: electrical. |
What is common in two eukaryotic proteins?
Here are the choices:
A. DNA
B. one domain
C. translation
D. cells | B: one domain. | |
What do you call egg-shaped galaxies, which are reddish to yellowish in color because they contain mostly old stars?
Here are the choices:
A. elliptical galaxies
B. conical galaxies
C. irregular galaxies
D. spiral galaxies | Pictured below is a typical elliptical galaxy ( Figure below ). As you might have guessed, elliptical galaxies are elliptical, or egg-shaped. The smallest elliptical galaxies are as small as some globular clusters. Giant elliptical galaxies can contain over a trillion stars. Elliptical galaxies are reddish to yellowish in color because they contain mostly old stars. | A: elliptical galaxies. |
When it was found that, without the force of gravity exerting pressure on the bones, bone mass was lost in astronauts, what kind of exercise provided an antidote?
Here are the choices:
A. sedentary
B. resistive
C. anaerobic
D. aerobic | Additionally, the yellow marrow, which is found in the central cavity of long bones along with red marrow, serves as a storage site for fat. 42 Structurally, the femur is a long bone, meaning its length is greater than its width, while the patella, a sesamoid bone, is small and round. Functionally, the femur acts as a lever, while the patella protects the patellar tendon from compressive forces. 44 The densely packed concentric rings of matrix in compact bone are ideal for resisting compressive forces, which is the function of compact bone. The open spaces of the trabeculated network of spongy bone allow spongy bone to support shifts in weight distribution, which is the function of spongy bone. 46 A single primary ossification center is present, during endochondral ossification, deep in the periosteal collar. Like the primary ossification center, secondary ossification centers are present during endochondral ossification, but they form later, and there are two of them, one in each epiphysis. 48 The internal callus is produced by cells in the endosteum and is composed of a fibrocartilaginous matrix. The external callus is produced by cells in the periosteum and consists of hyaline cartilage and bone. 50 Astronauts floating in space were not exerting significant pressure on their bones; they were “weightless. ” Without the force of gravity exerting pressure on the bones, bone mass was lost. To alleviate this condition, astronauts now do resistive exercise designed to apply forces to the bones and thus help keep them healthy. 52 Under “normal” conditions, receptors in the parathyroid glands bind blood calcium. When the receptors are full, the parathyroid gland stops secreting PTH. In the condition described, the parathyroid glands are not responding to the signal that there is sufficient calcium in the blood and they keep releasing PTH, which causes the bone to release more calcium into the blood. Ultimately, the bones become fragile and hypercalcemia can result. | B: resistive. |
What can occur during periods of heavy rain?
Here are the choices:
A. floods
B. volcanoes
C. glaciers
D. earthquakes | A: floods. | |
What type of energy can be used to change the position or shape of an object, thus giving it potential energy?
Here are the choices:
A. kinetic energy
B. binary energy
C. harmonic energy
D. static energy | Mechanical energy commonly changes between kinetic and potential energy. Kinetic energy is the energy of moving objects. Potential energy is energy that is stored in objects, typically because of their position or shape. Kinetic energy can be used to change the position or shape of an object, giving it potential energy. Potential energy gives the object the potential to move. If it does, the potential energy changes back to kinetic energy. | A: kinetic energy. |
What equals the output power divided by the input power?
Here are the choices:
A. potential
B. efficiency
C. inertia
D. output | ; The efficiency equals the output power divided by the input power. | B: efficiency. |
Overpopulation takes place when the number of organisms in an area exceeds what?
Here are the choices:
A. carrying capacity
B. consumers
C. predators
D. biome size | Overpopulation takes place when the number of organisms exceeds the carrying capacity of the region. What is the carrying capacity of Earth for humans? Are seven billion people the human carrying capacity? Nine billion? We don't know yet. | A: carrying capacity. |
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