Earth Science
Which of the following conditions is required for the rapid replenishment of an aquifer?
A.Permeable soil
B.Steeply sloped land
C.Direct sunlight
D.High atmospheric pressure
Option (A) is correct. Aquifers are underground layers of porous rock that hold groundwater. Water removed from an aquifer can be replenished naturally by the infiltration of precipitation into the ground, a process that occurs rapidly when the subsurface soil is permeable.
Which of the following human organs is responsible for the formation of sperm cells?
A.Pancreas
B.Thyroid
C.Ovary
D.Testis
Option (D) is correct. In human males, the testis is the organ in which the formation of sperm cells occurs.
The process by which a gas becomes a liquid is called
A.condensation
B.freezing
C.melting
D.reduction
Option (A) is correct. Condensation is the process by which a gas becomes a liquid.
In a demonstration of the Doppler effect, an observer who is standing still will most likely hear a sound’s pitch increase when the source of the sound does which of the following?
A.Remains motionless
B.Moves toward the observer
C.Moves away from the observer
D.Revolves in a circle around the observer
Option (B) is correct. An observer who is standing still will most likely hear a sound’s pitch increase when the source of the sound moves toward the observer. As the source of the sound moves toward the observer, each successive sound wave starts at a point closer to the observer, resulting in the sound waves reaching the observer with increasing frequency. Because the frequency of the sound waves increases, the observer perceives an increase in the sound’s pitch.
Which THREE of the following are generally acceptable rules for laboratory activities?
A.Students should wash their hands after mixing chemicals in the laboratory.
B.Students should inform the teacher immediately of any accidents or spills in the laboratory.
C.Students should use cracked glassware only when the teacher is in the laboratory.
D.Students should read instructions thoroughly before performing laboratory procedures.
Options (A), (B), and (D) are correct.
Which of the following processes most directly involves the movement of water from the atmosphere to Earth’s surface?
A.Infiltration
B.Precipitation
C.Transpiration
D.Sublimation
Option (B) is correct. Precipitation is the process by which atmospheric water falls to Earth’s surface in the form of rain, hail, sleet, or snow. Because atmospheric water returns to Earth’s surface primarily through the process of precipitation, it is an important part of the water cycle. Infiltration is the process by which water on Earth’s surface enters the subsurface soil and rock. Transpiration is the process by which water evaporates from plant leaves and enters the atmosphere. Sublimation is the process by which a substance transitions directly from the solid phase to the gas phase without going through the liquid phase.
Which of the following is the best example of an interaction between different biotic factors in an ecosystem?
A. caterpillar undergoing metamorphosis
B. plant absorbing sunlight
C. grazing animal eating plants
D. An icicle melting on a warm day
Correct Answer: C
Option (C) is correct. A grazing animal eating plants is an example of an interaction between two different biotic factors (an animal and the plants it eats) in an ecosystem. The metamorphosis of a caterpillar into a butterfly is an example of a type of insect life cycle. A plant absorbing sunlight is an example of an interaction between a biotic factor (a plant) and an abiotic factor (sunlight). An icicle melting on a warm day is an example of an interaction between two abiotic factors (water and temperature).
As a rock begins tumbling down a hillside, most of its gravitational potential energy is converted into
A.kinetic energy
B.thermal energy
C.chemical energy
D.nuclear energy
Option (A) is correct. Kinetic energy is the energy of motion. As the rock begins moving down the hillside under the influence of gravity, most of the rock’s gravitational potential energy is converted into kinetic energy.
In which of the following types of power plants would the normal generation of electricity most likely produce the least amount of carbon dioxide gas?
A.Nuclear-fueled
B.Coal-fueled
C.Natural gas–fueled
D.Oil-fueled
Option (A) is correct. Under normal operation, nuclear power plants release only water vapor from cooling towers. In contrast, the other types of power plants rely on the combustion of fossil fuels to generate electricity, which results in the release of significant amounts of carbon dioxide gas.
Which of the following is true about the formation of a covalent bond?
A.A covalent bond forms when electrons are shared between two atoms.
B.A covalent bond forms when one atom donates protons to another atom.
C.A covalent bond forms when two negatively charged atoms become attached to each other.
D.A covalent bond forms when the neutrons of one atom fuse with the neutrons of another atom.
Option (A) is correct. A covalent bond involves the sharing of one or more pairs of electrons between two atoms.
Which of the following best describes the approximate length of time it takes Earth to rotate once about its axis?
A.One hour
B.One day
C.One month
D.One year
Option (B) is correct. On average, it takes 24 hours, or one day, for Earth to rotate once about its axis. The rotation of Earth about its axis leads to the cycle of day and night.
Which of the following molecules is a product of cellular respiration and is used for energy transfer in cells?
A.ATPA T P
B.Carbon dioxide
C.Oxygen
D.Water
Option (A) is correct. ATPA T P is a small molecule that stores and transports chemical energy in cells. Cellular respiration is a multistep process in cells that uses chemical energy stored in glucose and other organic molecules to produce ATP.
A neutral atom becomes a positive ion when it loses one or more
A.electrons
B.neutrons
C.protons
D.nuclei
Option (A) is correct. Protons are positively charged, and electrons are negatively charged. A neutral atom has the same number of protons and electrons. A neutral atom becomes a positive ion when it loses one or more electrons, resulting in the ion having more positive charges than negative charges.
Which of the following identifies the ultimate source of genetic variation in a population of organisms?
A.Nonfatal injuries to some members of the population
B.Predators that catch and eat some members of the population
C.Changes in the DNAD N A of some members of the population
D.Seasonal weather changes in the area where the population is found
Option (C) is correct. Genetic variation results from random changes in genetic information. The genetic information of an organism is encoded in its DNAD N A, and heritable changes in the base pair sequences of DNAD N A are called mutations. Organisms in a population pass some mutations on to their offspring, and over multiple generations the accumulation of different mutations leads to greater genetic variation in the population.
Which of the following elements are most abundant in the Sun?
A.Hydrogen and helium
B.Oxygen and carbon
C.Nitrogen and phosphorus
D.Uranium and plutonium
Option (A) is correct. The composition of the Sun is approximately 99.9% hydrogen and helium.
During a total solar eclipse, the Moon is in which of the following phases?
A.New Moon
B.First quarter Moon
C.Full Moon
D.Third quarter Moon
Option (A) is correct. A total solar eclipse occurs when the Moon is between Earth and the Sun. The new Moon phase of the lunar cycle is when 0% of the sunlit portion of the Moon is visible from Earth, which also occurs when the Moon is between Earth and the Sun.
Which of the following is an important function of the digestive system?
A.Absorbing nutrients into the body
B.Transporting signals to and from different parts of the body
C.Providing structural support for the body
D.Protecting the body from ultraviolet radiation
Option (A) is correct. The digestive system includes organs that break down food into small molecules, which are then absorbed into the body. The primary location of absorption is the small intestine.
Researchers are measuring surface salinity in different areas of an ocean. In which of the following areas will the researchers most likely find the highest surface salinity?
A.An area in which cooler temperatures are causing heavy rainfall
B.An area in which warmer temperatures are causing icebergs to melt
C.An area in which river flow is causing a mixing of freshwater with seawater
D.An area in which warm, dry winds are causing a high rate of evaporation
Option (D) is correct. Salinity is a measure of the amount of dissolved salts in water. Processes that increase the concentration of dissolved salts in water lead to increased salinity. Evaporation is the process by which a liquid changes to a gas. Water evaporating from an ocean surface enters the atmosphere but leaves behind dissolved salts, resulting in an increase in the surface salinity in that area of the ocean. Heavy rainfall, the melting of icebergs, and inflow from a river are processes that add freshwater to the ocean, causing the surface salinity in those areas of the ocean to decrease.
Which of the following scientists did pioneering research on the properties of radioactive elements?
A.Isaac Newton
B.Marie Curie
C.Nicolaus Copernicus
D.Charles Darwin
Option (B) is correct. Marie and Pierre Curie are credited with the discovery of the radioactive elements polonium and radium. Marie Curie also investigated the properties of radioactive elements and their compounds.
An object is moving in a straight line at a constant speed. What will happen if a constant force is then applied to the object in the same direction in which the object is moving?
A.The object will stop moving.
B.The object will continue moving in the same direction but will slow down.
C.The object will continue moving in the same direction but will speed up.
D.The object will move in the opposite direction but at the same speed as before.
Option (C) is correct. When a constant force is applied to the object in the same direction in which the object is moving, the object will accelerate in that direction.
Which of the following best describes a galaxy?
A.A small celestial body composed of ice
B.A giant planet orbited by ten or more moons
C.A collection of planets revolving around a star
D.A large cluster of stars, dust, and gas
Option (D) is correct. A galaxy is a system composed of many stars, dust, and gas, which is held together by gravitational attraction.
Which of the following systems is responsible for the production of hormones?
A.Immune
B.Endocrine
C.Digestive
D.Skeletal
Option (B) is correct. The endocrine system includes glands that produce, store, and secrete hormones, which are carried by the circulatory system to their target tissues.
Which of the following best describes the type of chemical reaction that occurs when the acid HClH C l is mixed with the base NaOHN a O H in a solution?
A.Combustion
B.Decomposition
C.Neutralization
D.Dehydration
Option (C) is correct. Mixing the acid HClH C l with the base NaOHN a O H results in a neutralization reaction that produces water and the salt NaClN a C l.
Which THREE of the following statements about DNAD N A are true?
A.DNAD N A is a major source of cellular energy.
B.DNAD N A stores and transmits genetic information.
C.DNAD N A molecules have a double helix structure.
D.DNAD N A is found in animal cells but not bacterial cells.
E.DNAD N A is packaged into structures called chromosomes.
Options (B), (C), and (E) are correct. Genetic information is stored in DNAD N A in the form of different base pair sequences, and transmission of genetic information occurs when DNAD N A is replicated and transferred from one cell or organism to another. DNAD N A molecules have two complementary strands of nucleotides that form a double helix. In eukaryotic cells, long DNAD N A molecules are coiled around histone proteins into structures called chromosomes, which at certain times during the cell cycle become condensed into more compact structures that in some cases can be observed under a light microscope. DNAD N A is not typically used by cells as a source of energy. All organisms, including animals and bacteria, store genetic information as DNAD N A inside their cells.
CH4(g)+2O2(g)→CO2(g)+2H2O(g)
The balanced chemical equation shown above represents a reaction between methane ( CH4) and oxygen ( O2) that produces carbon dioxide ( CO2) and water ( H2O). Based on the balanced chemical equation, how many molecules of oxygen react with each molecule of methane?
A.One
B.Two
C.Three
D.Four
Option (B) is correct. In a chemical reaction between two substances, the atoms of the substances are rearranged to form other substances. In the chemical reaction represented by the equation, atoms in molecules of methane and oxygen are rearranged to form molecules of carbon dioxide and water. Because atoms are neither created nor destroyed in a chemical reaction, the equation has been balanced so that the same number of carbon, hydrogen, and oxygen atoms appear on both sides of the reaction arrow. Based on the balanced chemical equation, one molecule of methane reacts with two molecules of oxygen to produce one molecule of carbon dioxide and two molecules of water.