Environmental I...

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

Maximum threat to the world is from

Which of the following enhances B.O.D. of water ?

World climate is threatened by increase in the concentration of

The presence of ozone in the atmosphere of earth

Measurement of rate of oxygen utilisation by a unit volume of water over a period of time is to measure

The day-to-day condition of the atmosphere at a place with respect to the _______ is called the weather at that place.

Ozone is found in the atmosphere and helps to protect us from harmful radiation. Ozone is

Denitrification is caused by

Plantation of saplings on a large scale is celebrated as: