Most organisms obtain energy from food by the process of cellular respiration. Which 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.