Question

how the balance of oxygen is mentained over earth​

Answer 1

Answer:

By plants and other consumers.

Explanation:

as plants take carbon dioxide and give oxygen and consumers take oxygen and give carbon dioxide for plants. Hence the balance of oxygen is maintained on Earth.

Answer 2

Answer:

Human beings need oxygen for respiration. They take in oxygen and give out carbon dioxide. Plants on the other hand need carbon dioxide for photosynthesis. They take in the carbon dioxide exhaled by the humans, use it up and give out oxygen. Thus, the oxygen used comes back in the atmosphere. In this way the balance of oxygen is maintained.