Aprokaryote is most likely to use which of the following modes of metabolism to release energy if it is in an environment without oxygen, dies when exposed to oxygen, and uses fermentation?

a. photoautotroph
b. facultative anaerobe
c. heterotroph
d. obligate anaerobe

I think the correct answer from the choices listed above is option D. A prokaryote that release energy if it is in an environment without oxygen and dies when exposed to oxygen, and uses fermentation would most likely be an obligate anaerobe.  Obligate anaerobes are poisoned by oxygen, so they gather at the bottom of the tube where the oxygen concentration is lowest.

Ithink the answer is d.