Pollution affects our climate and environment in several ways, like acid rain, greenhouse effect and global warming, ozone layer depletion, etc. The earth's temperature is maintained by the balance of incoming and outgoing solar radiations. Solar energy from the sun passes through the atmosphere to the earth and reflected back into space. While greenhouses help plants thrive in cold winters, the greenhouse effect has become a major cause of global warming.

(i) Greenhouses are small houses specially constructed to grow plants during adverse climatic conditions. Choose the incorrect statement from the following options :

1. These houses are structures built with walls and roofs, made up of glass and other transparent materials.
2. The roofs and walls of these houses are covered with green grasses to maintain the internal temperature.
3. The glass panels all around the greenhouse let sunlight enter but do not allow the heat to escape.
4. Both 1 and 3

(ii) The rise in earth's temperature is called global warming which is caused due to many reasons. Choose the incorrect option from the statements given below :

1. Depletion of ozone layer in the atmosphere is the main cause of global warming.
2. Increased industrialisation, burning of fuels in houses and rising population release more carbon dioxide in the atmosphere, causing global warming.
3. Greenhouse gases accumulate in the atmosphere which prevent the escape of heat.
4. Deforestation is also an additional cause of global warming.

(iii) Ozone is an allotropic form of oxygen which forms a sort of a screen high up in the atmosphere. Though it is highly poisonous and harmful to all living organisms, it is essential for the existence of life on earth. Choose the incorrect option :

1. Ozone occurs in significant amounts in the stratosphere which absorbs ultraviolet radiations.
2. It prevents the harmful infrared rays coming down to the earth from the sun.
3. CFCs and HCFCs released from refrigerators and aerosol sprayers deplete ozone layer and create a hole in the ozone layer.
4. Depletion of ozone layer can cause skin cancer, genetic disorders, cataract, etc.

(i) The roofs and walls of these houses are covered with green grasses to maintain the internal temperature.

Reason — Greenhouses are made of glass or other transparent materials that allow sunlight to enter and help retain heat inside.

(ii) Depletion of ozone layer in the atmosphere is the main cause of global warming.

Reason — Global warming is mainly caused by the increased concentration of greenhouse gases in the atmosphere.

(iii) It prevents the harmful infrared rays coming down to the earth from the sun.

Reason — The ozone layer absorbs harmful ultraviolet rays, not infrared rays.