In the history of life on our planet, which event is referred to as 'oxygen revolution'?

Correct option is A

The correct answer is Introduction of photosynthesis.
· Oxygen revolution occurred ~2.5 billion years ago.
· Cyanobacteria began photosynthesizing, releasing oxygen.
· This oxygen accumulated in the atmosphere.
· It enabled aerobic respiration and evolution of complex life.
Information Booster:
· Also called the Great Oxidation Event.
· Led to formation of the ozone layer.
· Marked transition from reducing to oxidizing atmosphere.
· Evidence found in banded iron formations.