Question

Oxygen in atmosphere has been formed by _____

• A. Evaporation of water
• B. Metabolism of microorganisms
• C. Decaying organisms
• D. Photosynthesis of blue green algae

Answer 1

Answer:

D. Photosynthesis of blue green algae

• Millions of years back, it was due to photosynthesis of blue green algae that resulted in the formation of oxygen in atmosphere.

• It gave the foundation for evolution.