2025-26 Biology U3LP2 CFA SB5b Review

While gardening, Nora notices that her plants grow better when placed in sunlight. In the process of photosynthesis, sunlight is converted into

• chemical energy.

• nuclear energy.

• mechanical energy.

• kinetic energy.

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Imagine a salt marsh where a variety of animals and plants live together. The pyramid below shows the amount of energy transferred between organisms in this salt marsh. Which trophic level would lose the most useful energy as heat when organisms at that level feed on other organisms?

• 5

• 4

• 3

• 2

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Oliver is studying a forest ecosystem and notices that the amount of plant material is much greater than the amount of animal material at higher feeding levels. Which factor best explains why biomass decreases as trophic level increases in a food pyramid?

• Some of the energy is converted to heat.

• The survival rate of organisms gradually decreases.

• The availability of space decreases as feeding levels increase.

• Toxic chemicals get concentrated as they move up the food web.

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Imagine you are visiting the Everglades and observing the food web in action. Energy is transferred from organism to organism in this ecosystem. Some organisms, such as the leopard frog, are secondary consumers. Others, such as the grass carp, can be either primary or secondary consumers, depending on which organisms they consume. Based on your observations, which of the following populations in this food web provides the greatest amount of energy as a food source?

• raccoon

• grass carp

• bladderwort

• American alligator

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NGSS.MS-LS2-3

Charlotte is learning about the carbon cycle in her science class. She wonders how chemical reactions play a part in moving carbon through the environment. Which statement best describes the role of chemical reactions in the carbon cycle?

• Chemical reactions transform carbon into more common elements.

• Chemical reactions create carbon as a byproduct of other natural processes.

• Chemical reactions use carbon and reduce the total amount of carbon found on the planet.

• Chemical reactions incorporate carbon into compounds and release carbon from other compounds.

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Emma is learning about how carbon moves from the atmosphere into living things. Which mechanism helps carbon to cycle from the atmosphere to living organisms?

• tissue decomposition

• cellular respiration

• photosynthesis

• transpiration

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After a wildfire sweeps through a grassland ecosystem, most of the grasses are destroyed. The pyramid shows how biomass changes between trophic levels in this ecosystem. Which explains how the biomass at the top of the pyramid will change as a result of the fire?

• It will increase because the amount of energy lost as heat between the first trophic level and second trophic level will decrease.

• It will increase because the fire increases the efficiency of energy transfer and prey acquisition at higher trophic levels.

• It will decrease because the amount of chemical energy photosynthesis generates will not be enough to support higher trophic levels.

• It will decrease because there will be a greater number of organisms at the second trophic level to support the higher trophic levels.

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Sophia is part of a team that removes fallen trees from a local forest to reduce fire risk. The team is now considering how this practice might affect the health of the forest. Which impact would removing fallen trees from forests most likely have on forest health?

• increased risk of forest fire

• increased food sources for forest fungi

• decreased soil fertility by preventing nutrient recycling

• decreased forest vegetation by increasing sunlight penetration

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Olivia is studying how fossil fuels are formed in different environments. She learns that the presence of high temperatures during fossil-fuel formation results in a higher percentage of which product?

• tar

• coal

• crude oil

• natural gas

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NGSS.MS-ESS2-1

Olivia is learning about how plants get the nutrients they need to grow. She wonders how nitrogen from the air is changed into a form that plants can use. In which process does this happen?

• nitrification

• denitrification

• nitrogen saturation

• nitrogen fixation