Question

Which of the following is the MOST LIKELY explanation for what prevents Earth from running out of oxygen?

A. The overall reactions of photosynthesis and cellular respiration are the opposite of one another, therefore the products of one are the reactants of the other, creating a cycle.

B. The energy—and thus oxygen—flows for cellular respiration and photosynthesis take place in the same direction, and therefore build upon one another.

C. Cellular respiration is a process that deposits energy and oxygen, and photosynthesis withdraws energy and uses oxygen, therefore balancing each other.

D. Oxygen readily accepts electrons, so cellular respiration uses a negligible amount of oxygen.

E. Cellular respiration is balanced by fermentation, an alternative process of glucose metabolism which returns oxygen to the atmosphere.

Answer 1

The most likely explanation for what prevents Earth from running out of oxygen is the cyclical nature of photosynthesis and cellular respiration, where the output of one process is the input for the other.

Step-by-step explanation:

The MOST LIKELY explanation for what prevents Earth from running out of oxygen is option A: The overall reactions of photosynthesis and cellular respiration are the opposite of one another, therefore the products of one are the reactants of the other, creating a cycle. Photosynthesis consumes carbon dioxide and produces oxygen, which is then used in cellular respiration to produce ATP, carbon dioxide, and water. Conversely, cellular respiration consumes the oxygen produced during photosynthesis and releases carbon dioxide, which is then used in photosynthesis. This reciprocal relationship helps maintain a balance of oxygen and carbon dioxide in Earth's atmosphere.