Anything and everything that surrounds us is called as an environment. Our environment is made up of living and non living things.All these things are dependent upon eachother for their survival. Many physical factors like wind,soil and air are the vital ingredients for the life on earth. The each and every activity of an organism directly or indirectly affects the other. On of the inevitable happening in the environment is the food chain. It is the link by which energy is supplied from one tropic level to the next tropic level.