Biologists are fairly certain that oxygen was built up in the atmosphere by the development of photosynthesis. The production of oxygen and, therefore, the beginning of extensive aerobic life was made possible by the evolution of
A) fermentation.
B) photosystem I.
C) photosystem II.
D) glycolysis.
E) the nucleus.

Question

Quizplus · Accepted Answer

Biologists believe that oxygen was built up in the atmosphere by the development of photosynthesis. Specifically, oxygen-producing photosynthesis (known as oxygenic photosynthesis) arises from the evolution of photosystem II (PSII) in cyanobacteria and chloroplasts.

Biologists Are Fairly Certain That Oxygen Was Built Up in the Atmosphere