A carnivore is a consumer that feeds on flesh to obtain energy and nutrients. The energy flow begins with the sun’s energy, which is absorbed by plants in order to make glucose. Then, herbivores feed on plants. Later on, they are consumed by carnivores. Among the choices, letter D best describes the energy flow to a carnivore.

D. light energy – plant – herbivore – carnivore

When the trophic level increases, the amount of organic matter decreases. In this case, primary producers have the greatest amount of living organic matter, whereas the top level consumers have the least amount of living organic matter.

E. The amount of living organic matter decreases at each trophic level in the ecosystem.

According to the energy pyramid, 10% of the energy is transferred from one trophic level into the next. If the primary producers, which is in the first level, contain 100% energy, the second trophic level would acquire 10% of the energy. Then, the third trophic level would get 1%. In this case, since primary producers produce 5,000 energy units, there are 500 energy units that are available for the second trophic level and 50 energy units for the third trophic level.

B. 500 energy units (second trophic level)

Only letter A gives the best description of the role of plants in the carbon cycle. In the carbon cycle, plants absorb the carbon dioxide in the atmosphere during photosynthesis to produce chemical energy. In turn, consumers eat the plants to obtain energy then they release carbon dioxide during cellular respiration.

A. Plants transfer carbon in the atmosphere to carbohydrates in the biosphere.