The prebiotic atmosphere of the earth was of a reducing nature. It was transformed into a oxidising atmosphere of present day due to the emergence of

Options

A. cyanobacteria
B. angiosperms
C. photosynthetic protists
D. eukaryotic algae.

Answer

A

Explanation

The prebiotic atmosphere of the earth was of a reducing nature, i.e., no free oxygen was available. It was transformed into an oxidising atmosphere due to the emergence of cyanobacteria. They used water to get hydrogen and released oxygen into the atmosphere.