Question

How is O2 and CO2 maintained in the atmosphere​

Answer 1

O2 and co2 is maintained in the air by plants during photosynthesis and carbon dioxide is produced by humans and plants and animals during respiration

Answer 2

`0^(2)` released by plants during the process called photosynthesis and
`CO^(2)` released by humans, animals, plants, etc. during the process caled respiration.