The concentration of carbon dioxide in the atmosphere is increasing due to the current global trend of deforestation and increasing combustion of fossil fuels. A part of the sunlight incident on the earth reflected back in the form of infrared radiations. This infrared radiation are absorbed by the carbon dioxide molecules. hence, the envelope of CO₂  of the atmospheric air would be able to trap larger proportion of the infrared radiations if the concentration of CO₂ is increased, thereby heating the atmosphere.
This heating of the absorption of infrared earth's temperature and may cause melting of glacier and thereby flooding the coastal plains.
Greenhouse gases:
(i) CO ₂ ,  
(ii) Methane (CH₄ ) and
(iii) Nitrogen oxide.

The concentration of carbon dioxide in the atmosphere is increasing due to the current global trend of deforestation and increasing combustion of fossil fuels. A part of the sunlight incident on the earth reflected back in the form of infrared radiations. This infrared radiation are absorbed by the carbon dioxide molecules. hence, the envelope of CO₂  of the atmospheric air would be able to trap larger proportion of the infrared radiations if the concentration of CO₂ is increased, thereby heating the atmosphere.
This heating of the absorption of infrared earth's temperature and may cause melting of glacier and thereby flooding the coastal plains.
Greenhouse gases:
(i) CO₂ , 
(ii) Methane (CH₄ ) and
(iii) Nitrogen oxide.

There are two types of sources of water pollution. These are:
(i) The sources which are located to close to water source and discharge pollutants directly into the particular water source. These may be factories, power plants, underground coal mines and oil wells situated near to water sources. It is possible to treat the pollutants before their release into the water body.
(ii) Some sources are scattered and do not have specific situation for discharging pollutants into a particular water body. These are run-off water from agricultural fields, gardens, lawns, roads, logging sites, construction sites etc. It is very difficult to monitor, regulate and treat non-point sources.

Cause of Acid Rain: Dissolution of different oxides of nitrogen (e.g., \({ NO }_{ 2 }\)) and sulphur (e.g., \({ SO }_{ 2 }\)) in rain water in the atmosphere causes Acid Rain. These oxides of nitrogen and sulphur are produced due to combustion of fossil fuels.
Consequences of Acid Rain
(i) Acid rain cause increase in acidity of the fertile soil and also damages chlorophyll of leaves of crops and other plants. Thus, indirectly reduces crop yield.
(ii) Acid rain corrodes metal, stones and marble, painted surfaces etc. Thus, harms our heritage monuments, statues and buildings.
(iii) By acidifying water, acid rain also harms aquatic life.

The atmosphere prevents the sudden increase in temperature during the daylight hours. It slows down the escape of heat into outer space during the night. Thus, the atmosphere keeps the average temperature of the earth fairly steady.

Mineral cycle: Minerals such as sodium, potassium, iron, magnesium, etc. come directly from the earth's crust due to weathering of rocks. From soil they enter the ecosystem and are taken up by the plants. From plants, they pass into the herbivores and then into the carnivores. The excretion and decomposition of dead plants, herbivores and carnivores bring back these minerals into the soil.

In Biogeochemical cycles, decomposers play a major role. Decomposers decompose the dead bodies (or plant) and excreta of both plants and animals. During decomposition complex compounds are broken down into simple form (usable form). The compounds are released into nutrient pool (soil, water bodies, atmosphere). The elements are put back into circulation by plants through reabsorption.

(a) Terrestrial organisms require fresh water to carry out various biological processes which take place in their body.
(b) (i) Snow covered mountains
(ii) Ice caps at the two poles.

Yes, all organisms require water to stay alive because:
(i) all cellular processes take place in a water medium in the body.
(ii) all the substances are transported from one part of the to the other by water in dissolved or suspended form.

(i) Smog: Smog is defined as fog intensified by atmospheric pollutants. A thick cloud of water droplets or smoke suspended in the atmosphere at or near the earth's surface restricting or obscuring visibility is called fog.
(ii) Two types of diseases caused-
(a) Allergies
(b) Heart diseases/cancer

Harmful effects of air pollution
(i) Respiratory problems
(ii) Acid rain or Global warming.

The messages that the children sent out to the public on EARTH DAYwere:

• How would you feel if somebody drew a nail into you?
• Even trees feel the pain
• Do not nail advertisements on trees
• Do not nail advertisements on trees
• Do not throw plastic bags in parks,gardens,etc They spoil the advertisement Always collect them and throw them in dustbine
• Join the stufdents of Delhi in saving the greens.
  (b) similar activities could be carried out in any town and city and one needn't wait for the Earth day or environment day top act that it was only through actions that we could bring about a change in peoples attitudes
  (c) Social responsibility
  (2) Keep the environment clean.

(a) (1) Before selling of old fridge or AC to junk purchaser remove the CPC compressure Take care that its gas does not leak in the atmosphere
(2) While purchasing new air conditioner or refrigeration,keep in mind it is ozone friendly i.e..it should contain HFC (Hydro-fluro carbon) instead of CFC
(3) Many mattresses and pillows are made of chemicals which harm ozone, Beware of them and purchase only ozone friendly products.
(4) While purchasing room refreshers,paint,etc., check that they do not contain CFCs
(b) By organising campaigns on the above said point for protection of ozone layer amongst masses they depict the following values:
(1) Relationship of common man and community with the ozone layer.
(2) Environmental protection.

It is very necessary to replenish forests for the following reasons:
(i) Rainfall: Trees give out enormous amount of water during transpiration. This water vapour helps in the formation of rain clouds. If trees are destroyed and not replenished the rainfall in the area will reduce. This may lead to less number of trees to grow.
(ii) Soil erosion: If trees are cut at a large rate the soil becomes barren. The top soil which is rich in organic matter will be washed away by water or carried away by wind. Thus reduction in rainfall and soil erosion may lead to the formation of desert.
(iii) Carbon dioxide-oxygen balance: Forests have very large number of trees. They give out \({ O }_{ 2 }\) and take in \({ CO }_{ 2 }\) in day time by the process of photosynthesis. Thus they help in maintaining carbon dioxide-oxygen balance in the atmosphere.