Question

cellular respiration is...
the process by which cells communicate with other cells.
the process by which cells break down glucose into energy.
the process by which cells break light down into energy.

Explanation:

Cellular respiration is a biological process. It occurs in cells. The key is to break down glucose. This breakdown releases energy. The first option is about cell - to - cell communication, which is not cellular respiration. The third option is about breaking down light (which is related to photosynthesis, not cellular respiration).

Answer:

the process by which cells break down glucose into energy.