INTRODUCTION
- On our earth, oxygen is the richest element present.
- In the atmosphere, oxygen is present in the form of elements to the extent of 21%.
- In the earth’s crust, it is present in the combined form. Whereas, in the air, it is present in the form of CO2.
- It is found as oxides of most metals and silicon, and as carbonate, nitrate, sulfate, and other minerals in the earth’s crust.
- Oxygen is the essential component of biomolecules like nucleic acids, carbohydrates, fats, and proteins.
- The oxygen cycle means the cycle that maintains the level of oxygen in the atmosphere.
- In three processes, the oxygen from the atmosphere is being used, namely combustion, respiration, and the formation of oxides of nitrogen.
- Photosynthesis is the only process in which oxygen is returned back to the atmosphere. And in nature, this forms the outline of the oxygen cycle.
