Name the processes which maintain the balance between oxygen and carbon dioxide in the air. How is it done?

The main process in nature that helps in balancing the quantities of oxygen and carbon dioxide in air is photosynthesis that occurs in green plants. Photo means light and synthesis means putting together.

It is a process through which green plants prepare their food in presence of sunlight with the help of carbon dioxide and water. The food is prepared in the form of glucose (a carbohydrate) with the release of oxygen gas.

Carbon dioxide + Water $\xrightarrow[\text{chlorophyll}]{\text{light}}$ Glucose + Oxygen

• In photosynthesis, plants use carbon dioxide from the air, water from the soil and give out oxygen.
• This process takes place only in green plants because they contain a green pigment called chlorophyll which is able to trap solar energy from the sun.