Conserving energy has become need of the society and nature. As a responsible citizen of India I should follow the following steps for conservation of energy :
(i) Use energy wisely.
(ii) Practice three R's : Reduce, recycle and reuse.
(iii) Follow all the instructions including Do's and Don'ts, e.g., switch off the light when not in use. Use cycle for short distances. Avoid excess use of plastic or non bio-degradable substances etc.

In a village people burn wood and cow dung as a fuel for basic necessity. In other nearby village, they have a big biogas plant in which biowaste is used to prepare biogas. If we compare the situation of both villages, I will prefer to have biogas plant as it cleans the surroundings of biowaste. It is environment friendly, no pollution, produces electricity and cooking gas and at last waste can be used as manure.

Various constituents of petroleum and their uses:
(i) LPG: Fuel for home and industry.
(ii) Petrol: Motor fuel, aviation fuel, solvent for dry cleaning.
(iii) Kerosene: Fuel for stoves, lamps and for jet aircraft.
(iv) Diesel: Fuel for heavy motor vehicles and electric generators.
(v) Lubricating Oil: Lubrication
(vi) Paraffin wax: Ointments, candles, Vaseline etc.
(vii) Bitumen: Paints and road surfacing.

Characteristics of coal:
(i) Coal is a hard, black, combustible fossil fuel.
(ii) It mainly contains carbon and is a good source of energy.
(iii) When heated in air, coal burns and produces mainly carbon dioxide gas.
Uses of coal:
(i) It is used in thermal power plants to produce electricity.
(ii) It is used as a fuel in various industries.
(iii) It is used for the manufacture of coke, coal-tar and coal gas.

About 300 million years ago, the earth had dense forests in low lying wetland areas. Due to natural processes like flooding, these forests got buried under the soil and deposited as fossil. Due to high temperature and pressure, dead plants got slowly converted into coal.

Decantation can be used to separate a mixture of petroleum and water. The mixture is allowed to stand. Carefully, lighter layer can be poured and separated without disturbing the heavier one.

Disadvantages of using fossil fuels are
(i) It causes air pollution.
(ii) It causes global warming because they produce greenhouse gas, i.e. carbon dioxide on burning
(iii) The by-products of burning fuels cause acid rain which pollute water resources

Difference between coke and coal are as follows:

The various fractions of petroleum are
(i) Petroleum gas in liquid form (LPG)
(ii) Petrol
(iii) Kerosene
(iv) Diesel
(v) Lubricating oil
(vi) Paraffin wax
(vii) Bitumen

Exhaustible natural resources are as below: Coal, natural gas, petroleum, minerals, forests. Inexhaustible natural resources are as below: Air, sunlight, oxygen.

These resources are present in an unlimited quantity in nature and are not likely to be exhausted by human activities.

Fossil fuels are exhaustible natural resources because they are made by the decomposition of the dead remains of living organisms. These are present in limited quantity beneath the earth. Thus, it will come to an end by human usage.

Millions of years ago, the earth had dense forests in low lying wetland areas. Due to natural processes like flooding and earthquakes, these forests got buried under the soil. As more soil deposited over them, they were compressed. The temperature also rose as they sunk deeper and deeper. Under high pressure and high temperature, dead plants got slowly converted into coal. The process of conversion of dead vegetation into coal is called carbonisation.

Bitumen.

The advantages of using CNG and LPG as fuels are as follows :
(i) CNG and LPG are clean fuels.
(ii) They do not produce pollution.
(iii) They are easily available.
(iv) They can be used directly for burning.
(v) They are easy to transport.
(vi) Their cost is low.