questions stringlengths 37 1.22k | reasoning stringlengths 0 3.56k ⌀ | answers stringlengths 4 138 |
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The electrons in a water molecule are more concentrated around the more highly charged oxygen nucleus than around this?
Here are the choices:
A. helium nuclei
B. hydrogen nuclei
C. peroxide nuclei
D. carbon nuclei | We will find in Atomic Physics that the orbits of electrons are more properly viewed as electron clouds with the density of the cloud related to the probability of finding an electron in that location (as opposed to the definite locations and paths of planets in their orbits around the Sun). This cloud is shifted by th... | B: hydrogen nuclei. |
What is the layer of ground below the surface that is always frozen, even in the summer?
Here are the choices:
A. bedrock
B. upper crust
C. permafrost
D. tundra | Polar tundra climates occur near the poles. Tundra climates have permafrost. Permafrost is layer of ground below the surface that is always frozen, even in the summer. Only small plants, such as mosses, can grow in this climate. | C: permafrost. |
What is usually the prey of a protist?
Here are the choices:
A. bacteria
B. algae
C. pathogens
D. proteins | The protist wraps around its prey, which is usually bacteria. | A: bacteria. |
What concentrates wave energy or disperses it?
Here are the choices:
A. wave reflection
B. wave refraction
C. wave diffusion
D. a prism | Wave refraction either concentrates wave energy or disperses it. In quiet water areas, such as bays, wave energy is dispersed. This allows sand to be deposited. Land that sticks out into the water is eroded by the strong wave energy. The wave energy concentrates its power on the wave-cut cliff . | B: wave refraction. |
In plants and algae, photosynthesis takes place in which organelles?
Here are the choices:
A. stems
B. fibroblasts
C. chloroplasts
D. cells | In plants and algae, photosynthesis takes place in organelles called chloroplasts. Chloroplasts contain stacks of membranes called thylakoids, which contain chlorophyll. Thylakoids are surrounded by a fluid-filled space called stroma. | C: chloroplasts. |
What produces sound waves that travel outward in all directions in water?
Here are the choices:
A. amplifiers
B. echo chamber
C. ultrasound machines
D. echo sounders | During World War II, battleships and submarines carried echo sounders. Their goal was to locate enemy submarines ( Figure below ). Echo sounders produce sound waves that travel outward in all directions. The sound waves bounce off the nearest object and then return to the ship. Scientists know the speed of sound in sea... | D: echo sounders. |
The roots of a plant take in nutrients and what vital substance?
Here are the choices:
A. Ash
B. water
C. Soil
D. air | B: water. | |
Carbon fixation is the first step of what cycle involving light reactions?
Here are the choices:
A. water cycle
B. sun cycle
C. calvin cycle
D. life cycle | As Melvin Calvin discovered, carbon fixation is the first step of a cycle. Like an electron transport chain, the Calvin Cycle, shown in Figure below , transfers energy in small, controlled steps. Each step pushes molecules uphill in terms of energy content. Recall that in the electron transfer chain, excited electrons ... | C: calvin cycle. |
What are the attractive forces that occur between polar molecules called?
Here are the choices:
A. particle - dipole forces
B. ion-dipole forces
C. induced-dipole forces
D. dipole-dipole forces | Dipole-dipole forces are the attractive forces that occur between polar molecules. A molecule of hydrogen chloride has a partially positive hydrogen atom and a partially negative chlorine atom. In a collection of many hydrogen chloride molecules, they will align themselves so that the oppositely charged regions of neig... | D: dipole-dipole forces. |
The production of multiple copies of a single gene is called?
Here are the choices:
A. gene change
B. cell cloning
C. gene variation
D. gene cloning | D: gene cloning. | |
Fossil fuels are made out of what two objects?
Here are the choices:
A. soil and animals
B. plants and water
C. plants and animals
D. gases and animals | Fossil fuels are made from plants and animals that lived hundreds of millions of years ago. The plants and animals died. Their remains settled onto the ground and at the bottom of the sea. Layer upon layer of organic material was laid down. Eventually, the layers were buried very deeply. They experienced intense heat a... | C: plants and animals. |
Amoebas and paramecia are examples of what?
Here are the choices:
A. protozoa
B. bacteria
C. vertebrates
D. protists | Examples of protozoa include amoebas and paramecia. | A: protozoa. |
Name the bacteria that make food through photosynthesis and release oxygen into the air?
Here are the choices:
A. cyanobacteria
B. algae
C. phytoplankton
D. fusobacteria | Bacteria called cyanobacteria are very important. They are bluish green in color (see Figure below ) because they contain chlorophyll (but not chloroplasts, of course). They make food through photosynthesis and release oxygen into the air. These bacteria were probably responsible for adding oxygen to the air on early E... | A: cyanobacteria. |
What simple machine consists of a bar that rotates around a fixed point called the fulcrum?
Here are the choices:
A. catapult
B. lever
C. rotor
D. battering ram | A lever is a simple machine that consists of a bar that rotates around a fixed point called the fulcrum. There are three classes of levers. Depending on its class, a lever may have an ideal mechanical advantage that is less than, equal to, or greater than 1. First-class levers also change the direction of the input for... | B: lever. |
Which carbohydrate is produced by photosynthesis?
Here are the choices:
A. insulin
B. sugar
C. protein
D. glucose | Glucose is the carbohydrate produced by photosynthesis. Energy-rich glucose is delivered through your blood to each of your cells. | D: glucose. |
What term is used to describe the line of latitude right in the middle of the planet?
Here are the choices:
A. orbital
B. pole
C. equator
D. Prime Meridian | Lines of latitude circle around Earth. The equator is a line of latitude right in the middle of the planet. The equator is an equal distance from both the North and South Pole. If you know your latitude, you know how far you are north or south of the equator. | C: equator. |
What is the opening formed between adjacent vertebrae for the exit of a spinal nerve called?
Here are the choices:
A. intervertebral foramen
B. inferior vertebral notch
C. spinous process
D. sympathetic ganglion | Figure 7.24 Intervertebral Disc The bodies of adjacent vertebrae are separated and united by an intervertebral disc, which provides padding and allows for movements between adjacent vertebrae. The disc consists of a fibrous outer layer called the anulus fibrosus and a gel-like center called the nucleus pulposus. The in... | A: intervertebral foramen. |
What two planets is the asteroid belt found between?
Here are the choices:
A. saturn and uranus
B. earth and venus
C. mars and venus
D. mars and jupiter | Hundreds of thousands of asteroids have been found in our solar system. They are still being discovered at a rate of about 5,000 new asteroids per month! The majority are located in between the orbits of Mars and Jupiter. This region is called the asteroid belt , as shown in Figure below . There are many thousands of a... | D: mars and jupiter. |
Neon is an example of what kind of gas?
Here are the choices:
A. natural
B. ideal
C. noble
D. inert | Once we reach neon, a noble gas, all of the 2p orbitals will be completely full. Neon has a configuration of 1s 2 2s 2 2p 6 . Any further electrons will need to go in the next highest energy orbital, which would be the 3s orbital. | C: noble. |
Many organisms look very similar to other organisms because they may be from the same what?
Here are the choices:
A. species
B. nutrients
C. area
D. parasites | A: species. | |
What type of compound is hydrogen chloride?
Here are the choices:
A. polar
B. metal
C. ionic
D. covalent | The largest, most complex covalent molecules have thousands of atoms. Examples include proteins and carbohydrates, which are compounds in living things. The smallest, simplest covalent compounds have molecules with just two atoms. An example is hydrogen chloride (HCl). It consists of one hydrogen atom and one chlorine ... | D: covalent. |
What kind of volcanic eruptions are less deadly?
Here are the choices:
A. explosive
B. serial eruptions
C. non-dormant
D. non-explosive | Some volcanic eruptions are non-explosive ( Figure below ). This happens when there is little or no gas. The lava is thin, fluid and runny. It flows over the ground like a river. People generally have a lot of warning before a lava flow like this reaches them, so non-explosive eruptions are much less deadly. They may s... | D: non-explosive. |
Where do most ecosystems get their energy from?
Here are the choices:
A. water
B. earth
C. sun
D. heat | Most ecosystems get their energy from the Sun. Only producers can use sunlight to make usable energy. Producers convert the sunlight into chemical energy or food. Consumers get some of that energy when they eat producers. They also pass some of the energy on to other consumers when they are eaten. In this way, energy f... | C: sun. |
When a solute dissolves into a solvent what is that called?
Here are the choices:
A. mixing
B. enthalpy
C. viscosity
D. solubility | Enthalpy changes also occur when a solute undergoes the physical process of dissolving into a solvent. Hot packs and cold packs (see Figure below ) use this property. Many hot packs use calcium chloride, which releases heat when it dissolves according to the equation below. | B: enthalpy. |
The smallest part of an element that maintains the identity of that element is called what?
Here are the choices:
A. lattice
B. atom
C. neutron
D. nucleus | Note Sometimes the word pure is added to substance, but this is not absolutely necessary. By definition, any single substance is pure. The smallest part of an element that maintains the identity of that element is called an atom. Atoms are extremely tiny; to make a line 1 inch long, you would need 217 million iron atom... | B: atom. |
Varves form in lakes covered by what?
Here are the choices:
A. bridges
B. coral reef
C. ice
D. soot | Varves form in lakes covered by ice. Varves are useful to scientists for understanding climate. | C: ice. |
Speed takes distance and what else into account?
Here are the choices:
A. gravity
B. energy
C. time
D. matter | Speed just takes distance and time into account. How might direction be considered as well?. | C: time. |
Which division of the autonomic nervous system controls processes like digestion, heartbeat, and breathing?
Here are the choices:
A. dopaminergic
B. synaptic
C. endocrine
D. parasympathetic | The parasympathetic division controls internal organs and glands during the rest of the time. It controls processes like digestion, heartbeat, and breathing when there is not an emergency. | D: parasympathetic. |
What does the ovule develop into after fertilization?
Here are the choices:
A. zygote
B. germ
C. pollen
D. seed | An ovule is a female reproductive structure in seed plants. It contains a tiny female gametophyte. The gametophyte produces an egg cell. After the egg is fertilized by sperm, the ovule develops into a seed. | D: seed. |
What is a key factor in the growth of populations?
Here are the choices:
A. assimilation
B. legislation
C. gentrification
D. immigration | Moving into an area, or immigration, is a key factor in the growth of populations. Shown above is actual vintage luggage left by some of the millions of immigrants who came through Ellis Island and into the United States. | D: immigration. |
Air is said to reach what point, a term used by meteorologists, when humidity increases or temperature decreases?
Here are the choices:
A. its dip point
B. bubble point
C. its dew point
D. freezing point | Air reaches its dew point when humidity increases or temperature decreases. | C: its dew point. |
In neurons, what often involves gated sodium channels?
Here are the choices:
A. depolarization
B. fermentation
C. excitation
D. polarization | A: depolarization. | |
Line graphs are especially useful for showing changes over what?
Here are the choices:
A. time
B. space
C. energy
D. velocity | Line graphs are especially useful for showing changes over time. The line graph in Figure below shows how distance from school changed over time when some students went on a class trip. | A: time. |
After a massive eruption what will a mountain collapsing above an empty chamber create?
Here are the choices:
A. caldera
B. cavern
C. crater
D. valley | During a massive eruption all of the material may be ejected from a magma changer. Without support, the mountain above the empty chamber may collapse. This produces a huge caldera . Calderas are generally round, bowl-shaped formations like the picture in Figure below . | A: caldera. |
The posterior half of the foot is formed by seven tarsal bones. the most superior of these bones is called?
Here are the choices:
A. talus
B. metatarsal
C. patella
D. calcareous | Tarsal Bones The posterior half of the foot is formed by seven tarsal bones (Figure 8.19). The most superior bone is the talus. This has a relatively square-shaped, upper surface that articulates with the tibia and fibula to form the ankle joint. Three areas of articulation form the ankle joint: The superomedial surfac... | A: talus. |
What helps to regulate consciousness, arousal, and sleep states?
Here are the choices:
A. hypothalamus
B. cerebral cortex
C. hippocampus
D. thalamus | Basal Ganglia Interconnected brain areas called the basal ganglia (or basal nuclei), shown in Figure 35.20b, play important roles in movement control and posture. Damage to the basal ganglia, as in Parkinson’s disease, leads to motor impairments like a shuffling gait when walking. The basal ganglia also regulate motiva... | D: thalamus. |
Some fish will be over-fished to the point that their species ceases to exist, which is also known as what?
Here are the choices:
A. endangered
B. accumulation
C. abundance
D. extinction | will inevitably make it more difficult and costly to grow food. The world’s growing human population faces significant challenges in the increasing costs and other difficulties associated with producing food. Wild Food Sources In addition to growing crops and raising food animals, humans obtain food resources from wild... | D: extinction. |
Not surprisingly, what is the function of the most developed part of a bird's brain?
Here are the choices:
A. controlling digestion
B. controlling breeding
C. controlling flight
D. controlling thought | Birds have a large brain relative to the size of their body. Not surprisingly, the part of the brain that controls flight is the most developed part. The large brain size of birds is also reflected by their high level of intelligence and complex behavior. In fact, birds such as crows and ravens may be more intelligent ... | C: controlling flight. |
What type of roots enable a plant to grow on another plant?
Here are the choices:
A. mites
B. endemic
C. epiphytic
D. Sickness | Epiphytic roots enable a plant to grow on another plant. For example, the epiphytic roots of orchids develop a spongy tissue to absorb moisture. The banyan tree (Ficus sp. ) begins as an epiphyte, germinating in the branches of a host tree; aerial roots develop from the branches and eventually reach the ground, providi... | C: epiphytic. |
What is the distance north or south of the equator called?
Here are the choices:
A. longitude
B. latitude
C. circumference
D. elevation | Latitude is the distance north or south of the Equator. It is expressed as a number between 0° and 90° north or south. | B: latitude. |
In response to a cut, mast cells secrete histamines that cause nearby capillaries to do what?
Here are the choices:
A. narrow
B. harden
C. constrict
D. dilate | Figure 42.5 In response to a cut, mast cells secrete histamines that cause nearby capillaries to dilate. Neutrophils and monocytes leave the capillaries. Monocytes mature into macrophages. Neutrophils, dendritic cells and macrophages release chemicals to stimulate the inflammatory response. Neutrophils and macrophages ... | D: dilate. |
What is the term for an ionic compound that produces positive hydrogen ions when dissolved in water?
Here are the choices:
A. acid
B. base
C. sulfur
D. hydrocarbon | An acid is an ionic compound that produces positive hydrogen ions when dissolved in water. Acids taste sour and turn blue litmus paper red. | A: acid. |
The stems of all vascular plants get longer through primary growth. this occurs in primary meristem at the tips and ______ of the stems.
Here are the choices:
A. nodes
B. edges
C. bottoms
D. layers | The stems of all vascular plants get longer through primary growth. This occurs in primary meristem at the tips and nodes of the stems. Most stems also grow in thickness through secondary growth. This occurs in secondary meristem, which is located in and around the vascular tissues. Secondary growth forms secondary vas... | A: nodes. |
What kind of waves are electromagnetic waves?
Here are the choices:
A. transverse
B. curved
C. amplitude
D. inverse | In this lesson, you learned that electromagnetic waves are transverse waves. Like other transverse waves, electromagnetic waves have certain properties. | A: transverse. |
What process is involved in the formation of a waterfall, when a stream flows from an area of harder to softer rock?
Here are the choices:
A. evaporation
B. calcification
C. erosion
D. migration | Mountain streams may erode waterfalls. A waterfall forms where a stream flows from an area of harder to softer rock ( Figure below ). The water erodes the softer rock faster than the harder rock. This causes the stream bed to drop down, like a step. This creates a waterfall. As erosion continues, the waterfall graduall... | C: erosion. |
Meissner’s corpuscles are not as plentiful in the palms as they are in the what other part of the hand?
Here are the choices:
A. fingertips
B. cuticles
C. bones
D. fingernails | Which of the following statements about mechanoreceptors is false? a. Pacini corpuscles are found in both glabrous and hairy skin. Merkel’s disks are abundant on the fingertips and lips. Ruffini endings are encapsulated mechanoreceptors. Meissner’s corpuscles extend into the lower dermis. Meissner’s corpuscles, (shown ... | A: fingertips. |
What are the two types of earth crust?
Here are the choices:
A. reflective and continental
B. micro and continental
C. amorphous and continental
D. oceanic and continental | The crust is less than 1% of Earth by mass. The two types are oceanic crust and continental crust. | D: oceanic and continental. |
What is determined by the energy of the disturbance that causes the wave?
Here are the choices:
A. wave amplitude
B. frequency
C. wavelength
D. Ohm | Wave amplitude is determined by the energy of the disturbance that causes the wave. A wave caused by a disturbance with more energy has greater amplitude. | A: wave amplitude. |
What is made from the minerals in rocks known as bauxite?
Here are the choices:
A. coins
B. aluminum
C. glass
D. titanium | Aluminum is made from the minerals in rocks known as bauxite. | B: aluminum. |
What is a defining feature of deformed sedimentary rocks?
Here are the choices:
A. not solid
B. not horizontal
C. not magnetic
D. only horizontal | Sedimentary rocks that are not horizontal have been deformed. | B: not horizontal. |
Resemblance to other species can serve as protection to what category of species?
Here are the choices:
A. consumer
B. predator
C. producer
D. prey | D: prey. | |
What type of cells make up the epidermis of a leaf?
Here are the choices:
A. dermal cells
B. mesophyll
C. chloroplasts
D. endothermic cells | The epidermis of the leaf consists of a single layer of tightly-packed dermal cells. They secrete waxy cuticle to prevent evaporation of water from the leaf. The epidermis has tiny pores called stomata (singular, stoma) that control transpiration and gas exchange with the air. For photosynthesis, stomata must control t... | A: dermal cells. |
What carries warm or cold water throughout the world’s oceans?
Here are the choices:
A. pipes
B. gravity
C. earth rotation
D. ocean currents | Ocean currents carry warm or cold water throughout the world’s oceans. They help to even out the temperatures in the oceans. This also affects the temperature of the atmosphere and the climate around the world. Currents that are near shore have a direct impact on climate. They may make the climate much colder or warmer... | D: ocean currents. |
What type of resource cannot be replaced as easily as it is consumed?
Here are the choices:
A. renewable
B. nonrenewable
C. untapped
D. biological | A nonrenewable resource is one that cannot be replaced as easily as it is consumed. Fossil fuels are an example of nonrenewable resources. They take millions of years to form naturally, and so they cannot be replaced as fast as they are consumed. To take the place of fossil fuel use, alternative energy resources are be... | B: nonrenewable. |
What substances are involved in most of the chemical reactions that take place in organisms, including digestion?
Here are the choices:
A. proteins
B. enzymes
C. vitamins
D. hormones | Enzymes are involved in most of the chemical reactions that take place in organisms. About 4,000 such reactions are known to be catalyzed by enzymes, but the number may be even higher. In animals, an important function of enzymes is to help digest food. Digestive enzymes speed up reactions that break down large molecul... | B: enzymes. |
What occurs when the immune system is not working properly?
Here are the choices:
A. cancer
B. immunodeficiency
C. anemia
D. allergy | Immunodeficiency occurs when the immune system is not working properly. As a result, it cannot fight off pathogens that a normal immune system would be able to resist. Rarely, the problem is caused by a defective gene. More often, it is acquired during a person’s lifetime. Immunodeficiency may occur for a variety of re... | B: immunodeficiency. |
The force that a magnet exerts on certain materials is called what?
Here are the choices:
A. magnetic force
B. centripetal force
C. velocity force
D. stellar force | The force that a magnet exerts on certain materials, including other magnets, is called magnetic force . The force is exerted over a distance and includes forces of attraction and repulsion. North and south poles of two magnets attract each other, while two north poles or two south poles repel each other. A magnet can ... | A: magnetic force. |
What is applied to a rock to make it bend and flow?
Here are the choices:
A. phosphorus
B. stress
C. acid
D. weathering | The amount of stress on a rock may be greater than the rock’s strength. In that case, the rock will change and deform ( Figure below ). Deep within the Earth, the pressure is very great. A rock behaves like a stretched rubber band. When the stress stops, the rock goes back to its original shape. If more stress is appli... | B: stress. |
What is the function of chloroplasts that are found in plant and algal cells?
Here are the choices:
A. photosynthesis
B. glycolysis
C. mitosis
D. spermatogenesis | Actually, almost all organisms obtain their energy from photosynthetic organisms. For example, if a bird eats a caterpillar, then the bird gets the energy that the caterpillar gets from the plants it eats. So the bird indirectly gets energy that began with the glucose formed through photosynthesis. Therefore, the proce... | A: photosynthesis. |
What passes through the prostate gland immediately inferior to the bladder before passing below the pubic symphysis?
Here are the choices:
A. rectum
B. urethra
C. cerebellum
D. vagina | Male Urethra The male urethra passes through the prostate gland immediately inferior to the bladder before passing below the pubic symphysis (see Figure 25.3b). The length of the male urethra varies between men but averages 20 cm in length. It is divided into four regions: the preprostatic urethra, the prostatic urethr... | B: urethra. |
Terrestrial animals lose water by evaporation from their skin and which surfaces?
Here are the choices:
A. digestive
B. pulmonary
C. respiratory
D. anaerobic | C: respiratory. | |
What color are leukocytes blood cells?
Here are the choices:
A. black
B. red
C. white
D. blue | The chemicals that trigger an inflammatory response attract leukocytes to the site of injury or infection. Leukocytes are white blood cells. Their role is to fight infections and get rid of debris. Leukocytes may respond with either a nonspecific or a specific defense. | C: white. |
What is something that all machines must overcome?
Here are the choices:
A. temperature
B. stress
C. work
D. friction | The mechanical advantage of a simple machine such as a pulley is the factor by which the machine changes the force applied to it. The ideal mechanical advantage of a machine is its mechanical advantage in the absence of friction. All machines must overcome friction, so the ideal mechanical advantage is always somewhat ... | D: friction. |
The conservation of momentum principle can be applied to systems as different as a comet striking earth and a gas containing huge numbers of atoms and these?
Here are the choices:
A. particles
B. protons
C. ions
D. molecules | The conservation of momentum principle can be applied to systems as different as a comet striking Earth and a gas containing huge numbers of atoms and molecules. Conservation of momentum is violated only when the net external force is not zero. But another larger system can always be considered in which momentum is con... | D: molecules. |
What are the small units that comprise nucleic acids?
Here are the choices:
A. chromosomes
B. genes
C. nucleotides
D. filaments | DNA and RNA are nucleic acids. Nucleic acids are built of small units called nucleotides. | C: nucleotides. |
Minerals that are not pure elements are made of what?
Here are the choices:
A. isotopes
B. chemical compounds
C. noble gases
D. metalloids | Minerals that are not pure elements are made of chemical compounds. For example, the mineral quartz is made of the compound silicon dioxide, or SiO 2 . This compound has one atom of the element silicon for every two atoms of the element oxygen. | B: chemical compounds. |
What can be classified as monoprotic or polyprotic based on the number of acidic hydrogens they contain?
Here are the choices:
A. salts
B. ions
C. acids
D. cations | Acids can be classified as monoprotic or polyprotic based on the number of acidic hydrogens they contain. | C: acids. |
What is the top part of water able to receive enough sunlight for photosynthesis called?
Here are the choices:
A. fantasmic zone
B. photic zone
C. thymic zone
D. synthesis zone | Only the top 200 meters or so of water receive enough sunlight for photosynthesis. This part of the water is called the photic zone. Below 200 meters, there is too little sunlight for photosynthesis to take place. This part of the water is called the aphotic zone. In this zone, food must come from other sources. It may... | B: photic zone. |
Different media affect what property of light?
Here are the choices:
A. density
B. color
C. temperature
D. speed | The speed of light is different in different media. | D: speed. |
Signals from rods and cones can follow several different pathways in what structure of the eye?
Here are the choices:
A. aqueous humor
B. retina
C. aperture
D. lens | B: retina. | |
What is the term for getting used to something after being consistently exposed to it?
Here are the choices:
A. dissociation
B. habituation
C. modification
D. acceptance | One of the simplest ways of learning that occurs in just about all animals is habituation. Habituation means learning to get used to something after being exposed to it repeatedly. It usually involves getting used to something that is frightening or annoying but not dangerous. | B: habituation. |
What element do nuclear power plants use in fuel rods?
Here are the choices:
A. uranium
B. plutonium
C. boron
D. magnesium | Nuclear power plants use uranium in fuel rods. The fuel rods become nuclear waste. Nuclear waste can be dangerous for hundreds of thousands of years. | A: uranium. |
Where on earth do bacteria live?
Here are the choices:
A. blood
B. water
C. all environments
D. skin | Prokaryotes include Bacteria and Archaea. An individual prokaryote consists of a single cell without a nucleus. Bacteria live in virtually all environments on Earth. Archaea live everywhere on Earth, including extreme environments. | C: all environments. |
What type of waves radiate energy out from an earthquake's focus?
Here are the choices:
A. abnormal
B. Microwaves
C. seismic
D. volcanic | Geologists study earthquake waves to “see” Earth's interior. Waves of energy radiate out from an earthquake’s focus. These are called seismic waves ( Figure below ). Seismic waves change speed as they move through different materials. This causes them to bend. Some seismic waves do not travel through liquids or gases. ... | C: seismic. |
What is a popular treatment for kidney failure?
Here are the choices:
A. psychotherapy
B. dialysis
C. metastasis
D. electrolysis | Uncontrolled diabetes may damage capillaries of nephrons. As a result, the kidneys lose much of their ability to filter blood. This is called kidney failure . The only cure for kidney failure is a kidney transplant, but it can be treated with dialysis. Dialysis is a medical procedure in which blood is filtered through ... | B: dialysis. |
What is critical for the formation of hemoglobin?
Here are the choices:
A. salts
B. proteins
C. platelets
D. iron ions | Minerals Minerals in food are inorganic compounds that work with other nutrients to ensure the body functions properly. Minerals cannot be made in the body; they come from the diet. The amount of minerals in the body is small—only 4 percent of the total body mass—and most of that consists of the minerals that the body ... | D: iron ions. |
Which hormones work together to control the level of glucose in the blood?
Here are the choices:
A. testosterone and insulin
B. insulin and glucagon
C. insulin and estrogen
D. serotonin and glucagon | The pancreas is located near the stomach. Its hormones include insulin and glucagon. These two hormones work together to control the level of glucose in the blood. Insulin causes excess blood glucose to be taken up by the liver, which stores the glucose as glycogen. Glucagon stimulates the liver to break down glycogen ... | B: insulin and glucagon. |
What are the two basic parts that all flowering plants have in common?
Here are the choices:
A. leaf and petiole
B. blade and petiole
C. stalk and petiole
D. metal and petiole | Flowering vascular plants also have diverse leaves. However, the leaves of all flowering plants have two basic parts in common: the blade and petiole. The blade of the leaf is the relatively wide, flat part of the leaf that gathers sunlight and undergoes photosynthesis. The petiole is the part that attaches the leaf to... | B: blade and petiole. |
Salts are important in maintaining what balance of the blood?
Here are the choices:
A. kinetic
B. pulmonary
C. osmotic
D. homeostasis | C: osmotic. | |
What do some animals grow to protect themselves in winter?
Here are the choices:
A. thin skin
B. scales
C. antennae
D. thicker fur | D: thicker fur. | |
What weather phenomenon can raise sea level as much as 25 feet when low pressure pulls water upward?
Here are the choices:
A. earthquake surge
B. storm rise
C. cloud formation
D. storm surge | Some of the damage done by storms is from storm surge . Low pressure in a storm pulls water upward. Water piles up at a shoreline as storm winds push waves into the coast. Storm surge may raise sea level as much as 7.5 m (25 ft). This can be devastating in a shallow land area when winds, waves, and rain are intense. | D: storm surge. |
The action of sunlight on the skin triggers the body to produce what vitamin?
Here are the choices:
A. tissue d
B. Vitamin A
C. vitamin d
D. metabolic d | Milk and other dairy foods are not the only sources of calcium. This important nutrient is also found in green leafy vegetables, broccoli, and intact salmon and canned sardines with their soft bones. Nuts, beans, seeds, and shellfish provide calcium in smaller quantities. Except for fatty fish like salmon and tuna, or ... | C: vitamin d. |
What is heard when sound waves bounce back from a surface that they can't pass through?
Here are the choices:
A. echo
B. loop
C. radio
D. ultrasound | Did you ever hear an echo of your own voice? An echo occurs when sound waves bounce back from a surface that they can’t pass through. The woman pictured here is trying to create an echo by shouting toward a large building. When the sound waves strike the wall of the building, most of them bounce back toward the woman, ... | A: echo. |
What is hole that is dug or drilled through the ground down to an aquifer?
Here are the choices:
A. elevator
B. well
C. cave
D. big hole | Many people get their freshwater from an aquifer. They obtain the water through a well. A well is a hole that is dug or drilled through the ground down to an aquifer. | B: well. |
What protective substance covers the skin of most reptiles?
Here are the choices:
A. pores
B. hairs
C. feathers
D. scales | Reptiles are a class of tetrapod vertebrates that produce amniotic eggs. They include crocodiles, alligators, lizards, snakes, and turtles. The reptile class is one of the largest classes of vertebrates. It consists of all amniotes except birds and mammals. Reptiles have several adaptations for living on dry land that ... | D: scales. |
What step, involving placement of a substance on the stigma, precedes fertilization?
Here are the choices:
A. pollination
B. hibernation
C. spawning
D. mitosis | A: pollination. | |
What weather phenomenon is caused by strong warm updrafts from heated ground?
Here are the choices:
A. eruptions
B. earthquakes
C. thunderstorms
D. currents | Thunderstorms form when the ground is really hot ( Figure below ). The air near the ground becomes very warm and humid. This is true in some locations in late afternoon or early evening in spring and summer. The warm air rises rapidly, which creates strong updrafts. When the rising air cools, its water vapor condenses.... | C: thunderstorms. |
The older parts of what structures anchor the plant and transport water and solutes between the soil and shoots?
Here are the choices:
A. cells
B. leaves
C. bark
D. roots | D: roots. | |
What do you call a specialized type of plant tissue that transports water and nutrients throughout the plant?
Here are the choices:
A. cambrium layer
B. chloroplasm
C. vascular tissue
D. thermal tissue | Vascular seedless plants have vascular tissue, a specialized tissue that transports water and nutrients throughout the plant. | C: vascular tissue. |
The major fuel for the brain is which carbohydrate?
Here are the choices:
A. insulin
B. glucose
C. glutamate
D. sucrose | The brain is a marvelous organ. And it’s a hungry one, too. The major fuel for the brain is the carbohydrate glucose. The average adult brain represents about 2% of our body’s weight, but uses 25% of the glucose in the body. Moreover, specific areas of the brain use glucose at different rates. If you are concentrating ... | B: glucose. |
How do they classify tornadoes?
Here are the choices:
A. wind temperature
B. wind density
C. amount of destruction
D. wind speed | The winds of a tornado can reach very high speeds. The faster the winds blow, the greater the damage they cause. Wind speed and damage are used to classify tornadoes ( Table below ). | D: wind speed. |
What part of the body does hepatitis b effect?
Here are the choices:
A. heart
B. liver
C. joints
D. kidney | Hepatitis B is a disease of the liver. It is caused by a virus called hepatitis B, which can be passed through sexual activity. Hepatitis B causes vomiting. It also causes yellowing of the skin and eyes. The disease goes away on its own in some people. Other people are sick for the rest of their lives. In these people,... | B: liver. |
In the radiative zone, light particles called what can only travel a few millimeters before they hit another particle?
Here are the choices:
A. electrons
B. positrons
C. neutrons
D. photons | The radiative zone is the next layer out. It has a temperature of about 4 million °C. Energy from the core travels through the radiative zone. The energy travels at an extremely slow rate. Light particles are called photons . In the radiative zone, photons can only travel a few millimeters before they hit another parti... | D: photons. |
What natural resource can be damaged by the accumulation of too much salt?
Here are the choices:
A. sediment
B. forests
C. mineral
D. soil | Soils may also remain in place but become degraded. Soil is contaminated if too much salt accumulates. Soil can also be contaminated by pollutants. | D: soil. |
What secures teeth in the mouth?
Here are the choices:
A. cartilage
B. muscles
C. socket
D. plug | Anatomy of a Tooth The teeth are secured in the alveolar processes (sockets) of the maxilla and the mandible. Gingivae (commonly called the gums) are soft tissues that line the alveolar processes and surround the necks of the teeth. Teeth are also held in their sockets by a connective tissue called the periodontal liga... | C: socket. |
What is the production of offspring without gamete fusion called?
Here are the choices:
A. sexual reproduction
B. organic reproduction
C. asexual reproduction
D. ideal reproduction | C: asexual reproduction. | |
What causes continents to drift closer to the poles or the equator?
Here are the choices:
A. plate movements
B. tidal pull
C. wind
D. sediment movements | Plate movements cause continents to drift closer to the poles or the Equator. Ocean currents also shift when continents drift. All these changes can affect Earth’s temperature. | A: plate movements. |
What does a hypothesis become after many experiments provide results supporting it?
Here are the choices:
A. a fact
B. a theory
C. a study
D. a model | The scientific method is employed by scientists around the world, but it is not always conducted in the order above. Sometimes, hypothesis are formulated before observations are collected; sometimes observations are made before hypothesis are created. Regardless, it is important that scientists record their procedures ... | B: a theory. |
Geologists group rocks based on how they what?
Here are the choices:
A. look
B. move
C. form
D. dissove | Geologists group rocks based on how they form. There are three major rock types. Each will be described in more detail in the coming concepts. | C: form. |
What organelle contains the genetic material of the cell?
Here are the choices:
A. nucleus
B. meiosis
C. fetus
D. gamete | The nucleus contains the genetic material of the cell. | A: nucleus. |
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