Question

Explain how ;. The oxygen in air (or atmosphere) is replased

Answer 1

oxygen is intaken by humans and we expire CO2 and plants take in CO2 and give out O2.

Answer 2

Hello

It's simple. Animals intake O2 in air for  the process of respiration. The  major end product of respiration is CO2 which is released from our body.This CO2 is now used as main ingredient for photosynthesis by plants to make O2.

This is the cycle .

Hope you liked it.

Happy learning.