An organism is discovered that thrives in both the presence and absence of oxygen in the air. Curiously, the consumption of sugar increases as oxygen is removed from the organism's environment, even though the organism does not gain much weight. This organism
A) is photosynthetic.
B) is a normal member of the animal kingdom.
C) must utilize a molecule other than oxygen to accept electrons from the electron transport chain.
D) is a facultative anaerobe.
E) is an obligate anaerobe.

Question

Quizplus · Accepted Answer

The fact that the organism can thrive in both the presence and absence of oxygen suggests that it is a facultative anaerobe. The increase in sugar consumption when oxygen is removed may indicate a shift to anaerobic respiration, in which an alternative molecule accepts electrons from the electron transport chain. The organism not gaining much weight suggests that it is not photosynthetic or a normal member of the animal kingdom.

An Organism Is Discovered That Thrives in Both the Presence