Question

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

• A. Cyanobacteria
• B. Angiospherms
• C. Photosynthetic protists
• D. Eukaryotic algae

Answer 1

The correct option is A Cyanobacteria

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.

So, the correct answer is 'Cyanobacteria'.