Earth is an only planet in our solar system on which life exists. Constellation of factors is responsible for it such as presence of air, water, ozone layer and other resources. These resources are the naturally occurring material and are necessary for life. All living organisms together with atmosphere (air), hydrosphere (water) and lithosphere (outer crust of earth, i.e. soil) with all physiological factors prevailing in this region form Biosphere. Celebrates these days too…….. 21st March - World forest day