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.

Photosystem II

A complex of proteins and pigments in chloroplasts that captures light energy for use in photosynthesis, generating oxygen and driving electron transport.

Photosynthesis

The process by which green plants, algae, and some bacteria convert light energy, usually from the sun, into chemical energy stored in glucose, producing oxygen as a byproduct.

Aerobic Life

Life forms that require oxygen for their metabolic processes, typically through respiration, to produce energy.