Photosynthesis probably originated during the ________ eon and most likely used ________ as an electron donor.
A) Proterozoic; water
B) Archean; water
C) Archean; hydrogen sulfide
D) Proterozoic; hydrogen sulfide
E) Paleozoic; water

Question

Quizplus · Accepted Answer

Photosynthesis originated deep in the history of Earth, and oxygen was probably not the first electron acceptor used.

Photosynthesis Probably Originated During the ________ Eon and Most Likely