What process has led to the increasing oxygen concentration on the planet over the last 2.7 billion years?

Question

Quizplus · Accepted Answer

Photosynthesis has been the primary process responsible for increasing oxygen concentration on Earth over the last 2.7 billion years. Through photosynthesis, plants, algae, and cyanobacteria convert carbon dioxide and water into oxygen and glucose, thereby releasing oxygen into the atmosphere.

What Process Has Led to the Increasing Oxygen Concentration on the Planet