The Ozone Layer acts as a shield for us from very harmful UV rays. If we damage the Ozone Layer, we would put ourselves at an increasingly greater risk.

Methane is an odorless, colourless, flammable gas, with chemical formula CH₄. It is  the major constituent of natural gas, that is used as a fuel and is an important source of energy. It does not cause acid rain. 

One of the most common effects of UV exposure is erythema, also known as sunburn. Sunburn occurs when skin cells are damaged by the absorption of energy from UV rays.

This is a very important method for the prevention of soil pollution. An efficient system of disposal should be developed to deal with domestic solid waste. Industrial wastes can be treated physically, chemically and biologically, until they are less hazardous.

Global warming will not increase agricultural productivity.

In the past few decades, the causes of the majority of skin cancers have been identified, as the ultraviolet radiation. It is believed that ultraviolet rays specifically UV-B are one of the chief causes of skin cancers. In the case of skin cancer, the ultraviolet rays from the sun are usually the instigator.

The earth's atmosphere near the surface is composed primarily of Nitrogen and Oxygen. Together, the two comprise about 99% of the gas in the atmosphere. Percentage of Nitrogen in the atmosphere is about 78.084% which is the maximum amount.

Hydroelectric power or hydroelectricity is electrical power which is generated through the energy of falling instream water. This method of energy generation is viewed as very environmentally friendly by many people, since no waste occurs during energy generation.

All the above three options are the part of water use planning.

Organic means that the molecule contains carbon bonded to hydrogen. Only glucose with molecular formula C₆H₁₂O₆, has these elements so, it is the organic compound  present in all the  cells.

Chlorofluorocarbons are non-toxic, non-flammable and non-carcinogenic. They contain fluorine atoms, carbon atoms and chlorine atoms. CFCs released into the atmosphere accumulate in the stratosphere, where they have a deleterious effect on the ozone layer. In the stratosphere, the CFC molecules break down by the action of solar ultraviolet radiation and release their constituent chlorine atoms. These then react with the ozone molecules, resulting in their removal.

Biological Oxygen Demand (BOD) is a measure of the oxygen used by micro organisms to decompose the waste. If there is a large quantity of organic waste in the water supply, there will also be a lot of bacteria present , working to decompose this waste. In this case, the demand for oxygen will be high (due to all the bacteria) so the BOD level will be high. As the waste is consumed or dispersed through the water, BOD levels will begin to decline.

Dust particles in the atmosphere that arise from various sources, such as, soil dust lifted up by wind, volcanic eruptions and pollution.

Nylon is a substance that cannot be decomposed into environmentally safe waste materials, by the action of soil bacteria so, it is a non biodegradable substance.

Bacterias are capable of decomposing biodegradable substances only. Since polythene bags are non-biodegradable substances, it cannot be decomposed by bacteria.

In point source pollution, discharges occur to a water body at a single location, such as discharges from a chemical factory, urban runoff from a roadway storm drain, or from ships, at sea. So, municipal and industrial discharge pipes, are point source pollution.

Rain water does not cause groundwater contamination. It is used to provide drinking water, water for livestock, water for irrigation or to refill aquifers in a process, called groundwater recharge.

In the test of water contamination, the number of the colonies of coliform-bacteria Escherichia coli (E. coli) per 100 millilitres of water is counted. The result is expressed as 'Coliform Microbial Density' and indicates the extent of fecal matter present in it. 

Van Mahotsava Day is celebrated throughout the country in the first week (1^st to 7^th) of July every year. 

The ozone layer  refers to the ozone within stratosphere, where over 90% of the earth's ozone resides. It is not an environmental problem. A thinning ozone layer is a environmental problem. It leads to a number of serious health risks for humans. It causes greater incidences of skin cancer and cataract of the eye.

CFCs are not used for filling balloons.The most common gas used to fill a balloon is helium, which will make it float.

The destruction of the ozone shield is linked to to CFCs. Each of these products releases CFCs into the atmosphere. Once free, the CFCs float up to the ozone layer and remain there for 75 to 100 years, destroying the ozone molecules.

Organic compounds contain carbon and hydrogen bonds. Both water (H₂O) and salts (ex: NaCl) do not contain carbon & hydrogen, so they are inorganic in nature.

Edaphic factors which are related to the structure and composition of soil, including its physical and chemical properties, like soil and its types, soil profile, minerals, organic matter, soil water, soil organisms, are the abiotic factors of the ecosystem.

The micro organisms form a very large group of biotic components. They are found in all types of habitats and climatic conditions. They are members of bacteria, viruses and fungi group.