Air

Air is present all around us. That is a blanket of air surrounding the Earth called the utmost.It extends up to thousand kilometers above the surface of earth

Let us do a small activity

Take a deep breath, hold it as long as you can breathe out when you start feeling uncomfortable.Why do you think you cannot hold it any longer?

The activity shows us that we cannot live without air for more than a few minutes, the part of air that our body needs is oxygen. It is needed by our body cells to generate energy from food in the process called respiration. This energy is necessary for the body to perform all its functions.  If our body, does not get enough oxygen.It cannot perform, it's functions.Most living things on the Earth need oxygen to survive.The air gets thinner as we go up.Ninety nine percent of the air is found up to a height of thirty kilometers above the surface of earth