A science teacher asked his students of standard X to collect information about various energy sources and find how each one affects the environment. The teacher also motivated them to debate the merits and demerits of each source and select the best source of energy on that basis. Answer the following questions: (i) Mention two sources of energy based on their effect on environment which the students might have selected as the best. (ii) Which of the two energy sources renewable or non-renewable would have more demerits as compared to the other and why? (iii) Explain how the science teacher took this issue in today’ reference.

(i) So1ar energy and biomass energy- are two sources of energy which are considered as best form of energy from the environmental consequences.
(ii) Non-renewable sources of energy like wood, coal, petroleum etc., have more demerits as compared to the renewable sources like sun, flowing water, wind etc. Ii is because burning of fossil fuels cause pollution and more over these sources cannot be replenished at will.
(iii) The science teacher took this issue in today reference when our energy needs are increasing day by day and our fossil fuel resources are depleting at a fast rate. Moreorver, indiscriminate use of fossil fuels causes air, water and soil pollution which directly affects our health.