The ozone layer: Between 15 and 50 km above  earth is a thin layer of gas called 'ozone'. It protects earth from most of sun's harmful ultraviolet radiation. Too much radiation causes blindness in animals and skin cancer in people. In 1985, scientists discovered a hole in ozone layer in Antartica. They have recently discovered a smaller hole over arctic. The ozone layer is also becoming thinner over or locations of earth too. Scientists believe that over  last 10 years about 30% of ozone layer has disappeared. This damage is caused by chemicals. Choose right statement(s) from following.