how is the oxygen content maintained in the environment?
 

Dear student,
Please find below the answer:

Gases such as oxygen and carbon dioxide present in the air play an important role in the survival of organisms. The content of oxygen is maintained in the environment by green plants through respiration and photosynthesis. Plants (as well as animals) consume oxygen for respiration and oxygen is released as a by-product by green plants during the process of photosynthesis. 

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