Preparation Manual

Domain XIV—Nature of Science

Competency 043—Understand principles and procedures of scientific inquiry.

1. A scientist plants 100 bean seeds to investigate the effect of soil pH on growth rate and flowering. The seeds are planted in two large containers with 50 seeds in each container. The soil in one of the containers has a pH of 4, while the soil in the other container has a pH of 10. Which of the following changes to the experimental design would most improve the usefulness of the results?

1. increasing the number of plants in each group to reduce the effects of individual variability
2. limiting the dependent variables to either flowering or growth rate
3. planting a group of seeds in soil with a neutral pH to serve as a control
4. placing the seeds in individual pots so they do not crowd each other

AnswerEnter to expand or collapse answer.Answer expanded

Option C is correct. This question requires the examinee to demonstrate knowledge of the principles and procedures for designing and carrying out scientific investigations. In this experiment, since one of the containers contains acidic soil (i.e., soil having a pH of 4) and one of the containers has basic soil (i.e., soil having a pH of 10), an appropriate control would be to include a container that has soil of neutral pH (i.e., soil having a pH of 7).

Competency 044—Understand the history and nature of science.

2. In working out the theory of evolution, Charles Darwin was strongly influenced by which of the following developments in the sciences?

1. the hypothesis that Earth had changed gradually over long periods of time
2. the discovery that cells were the basic unit of living organisms
3. the recognition that Earth's crust was composed of shifting tectonic plates
4. the discovery that ancient humans lived in Africa millions of years ago

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Option A is correct. This question requires the examinee to demonstrate knowledge of the historical development of major scientific ideas. Darwin's theory of evolution by natural selection requires a long time frame over which to work. The work of two geologists, James Hutton and Charles Lyell, suggested that Earth had changed gradually over long periods of time, supporting Darwin's theory.

Competency 045—Understand the relationships between science, technology, engineering, mathematics, and society.

3. In which of the following scenarios does the government most directly affect the work of scientists?

1. The Food and Drug Administration evaluates the efficacy of a new medical device.
2. Politicians running for office debate the potential risks to humanity of global warming.
3. The governor of a large state announces new energy conservation measures for public buildings.
4. Congress votes to support increased funding for research at the National Institutes of Health.

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Option D is correct. This question requires the examinee to analyze the relationship between science and society. Government funding for research influences the work of scientists by encouraging them to work in funded areas of science and by providing funds for scientists to continue their work.

Domain XV—Physical Science

Competency 046—Understand the properties and characteristics of matter.

4. Which of the following is predicted by the kinetic theory of matter?

1. The electrons surrounding an atom are in constant motion.
2. The pressure of a gas will decrease if its volume is increased.
3. The density of a solid depends on its composition.
4. The charge of the atomic nucleus depends on its mass.

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Option B is correct. This question requires the examinee to recognize historic and contemporary theories of atomic structure and the kinetic theory of matter. According to the kinetic theory of matter, pressure in a gas-filled container results from collisions between molecules of gas and the sides of the container. If the volume of a container is increased, molecules will travel greater distances before striking the walls, and the collisions will therefore occur less frequently. This will result in a reduced pressure.

Competency 047—Understand physical and chemical changes in matter.

5. Use the balanced chemical equation below to answer the question that follows.

CaCO₃ → CaO + CO₂ CaCO₃ right arrow CaO plus CO₂

What is the mass of calcium oxide (CaO) that is produced by heating 80.0 g of calcium carbonate (CaCO₃)?

1. 44.8 g
2. 47.7 g
3. 65.9 g
4. 70.2 g

AnswerEnter to expand or collapse answer.Answer expanded

Option A is correct. This question requires the examinee to apply knowledge of chemical formulas, the mole concept, and chemical equations to solve problems. Since the reaction is already written in balanced form, one mole of CaO is produced for each mole of CaCO₃ that reacts. The molecular weight of CaCO₃ is the sum of the atomic weights of the atoms in CaCO₃. The molecular weight of CaCO₃ is 1(40 amu) + 1(12 amu) + 3(16 amu) = 100 amu 1 left parenthesis 40 amu right parenthesis plus 1 left parenthesis 12 amu right parenthesis plus 3 left parenthesis 16 amu right parenthesis equals 100 amu. This means that CaCO₃ has a mass of 100 g per mole. Therefore, 80.0 g of CaCO₃ represents 0.8 moles of CaCO₃ and must produce 0.8 moles of CaO. CaO has a molecular weight of 1(40 amu) + 1(16 amu) = 56 amu 1 left parenthesis 40 amu right parenthesis plus 1 left parenthesis 16 amu right parenthesis equals 56 amu, and 0.8 moles of CaO has a mass of (0.8) × (56) left parenthesis 0.8 right parenthesis times left parenthesis 56 right parenthesis or 44.8 g.

Competency 048—Understand the characteristics and transformations of different forms of energy.

6. Which of the electric circuits shown below will have the two brightest lights?

AnswerEnter to expand or collapse answer.Answer expanded

Option C is correct. This question requires the examinee to analyze characteristics of Ohm's law and series and parallel circuits. The brightness of an electric lamp is related to the amount of current through the lamp. Current in a circuit is directly proportional to voltage and inversely proportional to resistance. The circuits in responses A and C have a voltage of 3 V since they each have two 1.5 V cells in series. The difference between these two circuits is that in response A the lamps are in series, and in choice C the lamps are parallel. Two resistances in series have a greater total resistance than the same two resistances in parallel.

Competency 049—Understand relationships between force, mass, and motion.

7. A 10 kg mass is suspended by two cables. In which of the following situations will the tension in the cable labeled X be the greatest?

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Option B is correct. This question requires the examinee to solve problems involving force, mass, and motion. In response D, the mass is supported symmetrically by two cables of equal length. The two cables must share the load equally. In the case in which the mass is supported by a single vertical cable and hangs straight down (not shown), the cable would support all of the mass. Response B is closest to this situation and therefore has the greatest tension.

Competency 050—Understand characteristics and properties of mechanical and electromagnetic waves.

8. Sound waves travel at a different speed in warm air than they do in colder air. Which of the following explains why sound waves travel differently in warm air as opposed to cold air?

1. In warmer air, sound waves travel more rapidly because of the greater kinetic energy of the air molecules.
2. In colder air, sound waves are transmitted more rapidly due to the greater density of the air.
3. In warmer air, sound waves propagate more slowly because they are disrupted by convection currents.
4. In colder air, sound waves are transmitted more slowly due to the higher pressure of cool air masses.

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Option A is correct. This question requires the examinee to analyze the properties and propagation of sound in a variety of situations. Sound is transmitted as a disturbance of the medium in which it is traveling. The movement of the sound waves is due, in part, to the kinetic energy of the molecules of the conducting medium, in this case air. The molecules in warm air have greater kinetic energy than those in cooler air, and therefore allow the wave to travel at a greater velocity.

Domain XVI—Life Science

Competency 051—Understand the characteristics, organization, and processes of cells.

9. The folding of the internal membrane of the mitochondria serves which of the following purposes?

1. increasing the number of separate compartments in which proteins can be assembled
2. increasing the capacity to filter waste products produced during the process of cellular respiration
3. increasing the capacity to absorb enzymes needed to regulate cell division
4. increasing the surface area over which energy-releasing chemical reactions take place

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Option D is correct. This question requires the examinee to analyze the structure and function of cell organelles in eukaryotic cells. Many of the reactions involved in cellular respiration occur on the membranes of mitochondria. The folding of the internal membrane serves to increase its surface area, thereby providing more surface on which reactions can take place.

Competency 052—Understand characteristics and life processes of living organisms.

10. Many reef-forming corals form a symbiotic relationship with unicellular algae. Which of the following best describes the primary benefit to the corals from this relationship?

1. The corals obtain much of their energy from photosynthetic activity of the algae.
2. The algae are toxic to most fish and reduce predation by small fish on coral populations.
3. The corals can maintain a higher internal temperature due to heat generated by metabolic processes of the algae.
4. The algae attract small herbivorous fish and invertebrates, which are a major food source of the corals.

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Option A is correct. This question requires the examinee to analyze how organisms obtain, use, and store matter and energy. Photosynthetic algae called zooxanthellae live within coral polyps and produce oxygen and nutrients needed by the coral.

Competency 053—Understand the concepts and principles related to genetics, the theory of evolution, and the classification of organisms.

11. In which of the following scenarios is a species most likely to undergo evolutionary change?

1. A small population of a species of rodent is isolated permanently from the rest of its species by a natural disaster.
2. A migratory species of caribou is substantially reduced by predators during a very cold winter.
3. A species of invasive weed spreads rapidly along highways after being accidentally introduced.
4. A species of insect experiences rapid population growth during an unusually warm summer.

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Option A is correct. This question requires the examinee to apply knowledge of the principles and evidence of biological evolution to explain how species change over time. Geographic isolation of a species separates the species reproductively from other members of the species. This results in the isolated population taking a different evolutionary path than the main population due to genetic drift and differences in environmental pressures.

Competency 054—Understand characteristics of different biomes, relationships between organisms, population dynamics, and the flow of matter and energy through ecosystems.

12. Plants of the pea family use which of the following strategies to obtain a portion of their nitrogen requirement?

1. absorbing atmospheric nitrogen through the stomata in their leaves and stems
2. breaking down amino acids found in decaying soil humus into elemental nitrogen
3. hosting bacteria in their roots that transform gaseous nitrogen into useable nitrogen compounds
4. taking in rainwater that contains dissolved elemental nitrogen through leaf pores

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Option C is correct. This question requires the examinee to demonstrate knowledge of biotic and abiotic factors that affect population dynamics in ecosystems, including competition, resource availability, and niche and habitat requirements. Although approximately 78% of the atmosphere is made up of nitrogen, that nitrogen is not in a form that is useable by most organisms. Many plants, including pea plants, have close biological relationships with bacteria that are able to use atmospheric nitrogen, and in the process they convert the nitrogen to a form useful to the host plant.

Domain XVII—Earth and Space Science

Competency 055—Understand the history of Earth, characteristics of Earth materials and resources, and the geologic processes that shape Earth.

13. The conclusion that Earth's outer core is liquid is based on which of the following evidence?

1. the characteristics of minerals retrieved from deep-ocean drilling
2. the changes in Earth's magnetic field recorded over the past century
3. the composition of igneous rocks from major volcanic eruptions
4. the behavior of seismic waves as they travel through Earth's interior

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Option D is correct. This question requires the examinee to demonstrate knowledge of Earth's formation, history, and structure, as well as supporting geologic evidence. Since seismic waves behave differently in different materials, the behavior of the waves can be used to deduce geologic structure. The behavior of these waves indicates that Earth's outer core is liquid.

Competency 056—Understand characteristics and properties of the hydrosphere.

14. Which of the following factors is primarily responsible for the worldwide change in sea level that has occurred in the past 15,000 years?

1. thermal expansion of the oceans
2. tectonic uplift of continental shelves
3. isostatic uplift of coastal regions
4. melting of continental glaciers

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Option D is correct. This question requires the examinee to identify the processes and characteristics of marine and freshwater systems, including oceans and glaciers. Sea level has been rising at a slow rate for approximately 15,000 years, and over the past 100 years this rise has been accelerating. The change in sea level over the past 15,000 years has been due primarily to the melting and retreating of continental glaciers.

Competency 057—Understand Earth's atmosphere, weather, and climate.

15. The polar front jet stream and the subtropical jet stream are located in which layer of the atmosphere?

1. the lower mesosphere
2. the tropopause
3. the upper stratosphere
4. the stratopause

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Option B is correct. This question requires the examinee to demonstrate knowledge of the structure and characteristics of the different layers of the atmosphere. The polar front jet stream is at an elevation of approximately 7 km to 12 km above sea level. The subtropical jet stream is at an elevation of approximately 10 km to 16 km above sea level. Since the troposphere extends from Earth's surface to approximately 20 km above sea level, the polar front and subtropical jet streams are within the tropopause.

Competency 058—Understand characteristics of the solar system and the universe.

16.
The diagram is not to scale. Earth is shown in four equidistant points on its orbital path, numbered counterclockwise, with position 1 at the top of the diagram. In each position, Earth's axis is shown tilted to the right, and the left half of the moon's orbit is shown with a dashed line. In position 1, the moon is shown on the far side of Earth from the sun, placing it at the point between the solid line and the dashed line portions of its orbit. In position 2, the moon is shown on the near side of Earth from the sun, placing it at the midpoint of the solid line portion of its orbit. In position 3, the moon is shown on the near side of Earth from the sun, placing it at the point between the solid line and the dashed line portions of its orbit. In position 4, the moon is shown on the far side of Earth from the sun, placing it at the midpoint of the solid line portion of its orbit.
The orbit of the moon is inclined 5 degrees from the plane that contains the sun and Earth. The moon is below the Earth-sun plane in those parts of the moon's orbit that are shown with a dashed line in the diagram above. Given the moon's inclined orbit, a solar eclipse would most likely occur in which of the positions shown in the diagram?

1. position 1
2. position 2
3. position 3
4. position 4

AnswerEnter to expand or collapse answer.Answer expanded

Option C is correct. This question requires the examinee to analyze the interactions of the sun, moon, and Earth and the effects of these interactions on Earth. The moon will cast its shadow on Earth, producing a solar eclipse when the moon is between the sun and Earth and in the Earth-sun plane. In the diagram, the moon is in the Earth-sun plane when it is passing from the part of its orbit indicated by the dashed line (i.e., below the plane) to the part of its orbit indicated by the solid line (i.e., above the plane). The response that shows the moon in this position and between the sun and Earth is response C.