Question

How do plants and animals maintain the balance of oxygen and carbon dioxide in the air?

Answer 1

1. Respiration in plants:
   During respiration, plants take in oxygen and release carbon-di-oxide, just as animals also do. Gaseous exchange with air in the atmosphere takes place in plants with stomata.
2. Photosynthesis:
   During photosynthesis, carbon-di-oxide from the air and water from the soil react in the presence of sunlight to produce food. Plants release oxygen during photosynthesis which is much more than the oxygen consumed by the plants during respiration.
3. Respiration in animats:
   When we breathe in the air, the oxygen present in the air reacts chemically with digested food within the body to produce carbon-di-oxide gas. The inhaled air contains more oxygen while the exhaled air contains more carbon-di-oxide.
   So plants sent out more oxygen during photosynthesis. Animals sent out more carbon-di-oxide during respiration. Plants take carbon-di-oxide for photosynthesis. Animals take oxygen during respiration. So plants and animals maintain the balance of oxygen and carbon-di-oxide in the air.