Which statement best describes the relationship between photosynthesis and cellular respiration?

• A. Photosynthesis and respiration are unrelated processes.
• B. Photosynthesis releases energy; respiration stores energy; they cycle energy.
• C. Photosynthesis stores energy as glucose; cellular respiration releases energy from glucose; they form a cycle of energy transfer in ecosystems.
• D. Both processes occur only in animals.

Answer: (C)

Photosynthesis and cellular respiration are two connected ways organisms handle energy. In photosynthesis, light energy is captured and stored as chemical energy in glucose. In cellular respiration, that chemical energy is released to make ATP, the cell’s usable form of energy.

They are linked because the glucose and oxygen produced by photosynthesis are the inputs used in respiration, and the carbon dioxide and water produced by respiration are the inputs for photosynthesis. This connection ties the two processes together and supports energy transfer within ecosystems.

That description fits best because it accurately describes energy storage in glucose during photosynthesis, energy release during respiration, and their mutual dependence forming a cycle of energy flow in the environment. The other statements aren’t correct: photosynthesis and respiration are not unrelated; respiration does not store energy, it releases it; and photosynthesis occurs in plants (and some microbes), not only animals.