Question

pretest: unit 3
in the image below, what molecule is being released by cellular respiration and used in photosynthesis?
a. h₂o
b. o₂
c. c₆h₁₂o₆

Explanation:

Cellular respiration releases carbon - dioxide ($CO_2$), which is used as a reactant in photosynthesis. However, among the given options, the key gas product of cellular respiration that is used in photosynthesis is oxygen. In cellular respiration, glucose is broken down in the presence of oxygen to release energy, and oxygen is a by - product. In photosynthesis, plants use carbon - dioxide and water to produce glucose and oxygen, where the oxygen released by photosynthesis is used by animals for cellular respiration and the oxygen produced by cellular respiration is used in the light - independent reactions of photosynthesis.

Answer:

B. $O_2$