Why is it necessa

Human beings are an important part of the environment. But human activities change the environment and the changes in the environment affect life on earth.

For example: An environmental problem caused by human activities is depletion of ozone layer. If the ozone layer in the atmosphere disappears completely, then all the extremely harmful ultraviolet radiations coming from the Sun would reach the earth and would cause skin cancer and other ailments. Therefore it is necessary to conserve our environment.