Oxygen is circulated in nature. What role do living organisms play in this process?

Living organisms play a key role in the oxygen cycle. Most plants produce oxygen during photosynthesis by absorbing carbon dioxide and releasing oxygen and producing glucose. Phytoplankton also produces 50% of the oxygen in the atmosphere. The fauna absorbs oxygen. Of course, plants also absorb oxygen, but this happens at night. So oxygen is one of the key substances for the life of living organisms, and living organisms are the main source of oxygen production in the atmosphere.