Ozone layer of the Earth’s atmosphere is important for the living organisms because it prevents entry of ultra-violet rays.The ozone-oxygen cycle is the process by which ozone is continually regenerated in the Earth's stratosphere, converting ultraviolet radiation (UV) into heat. This cycle keeps the ozone layer in a stable balance while protecting the lower atmosphere from UV radiation, which is harmful to most living beings. It is also one of the two major sources of heat in the stratosphere (the other being the kinetic energy released when O2 is photolysed into O atoms)