Question

Why doesnt the level of
oxygen in the atmosphere
decrease?​

Answer 1

Explanation:

the percentage of oxygen in the atmosphere is constant for many years and does not decrease because the green plants which are capable of photosynthesis take up CO2 from the atmosphere and produce O2 in return. It is this process which keeps the oxygen levels fairly constant

Answer 2

Answer:

Yet, the percentage of oxygen in the atmosphere is constant for many years and does not decrease because the green plants which are capable of photosynthesis take up CO2 from the atmosphere and produce O2 in return. It is this process which keeps the oxygen levels fairly constant.