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Chapter 12: A Clean World, A. Tick (3) the correct answer, , 1. (c) 2. (c) 3. (a) 4.(c) 5.(c), B. Fill in the blanks., 1. air pollution 2. air pollution 3. carbon dioxide 4.deafness or headache 5. water, , C. Write 'T' for true and 'F' for false statements., , LF, , 2.F 3.7 4.T 5.F, , D. Answer the following questions in short., , 1,, 2., 3., 4, 5., , Land, water and air., , Contamination of atmosphere by human activities is called pollution., , Jaundice and cholera., , The harmful substances which pollute air, water and land are called pollutants., Detergents, soap and polythene., , —. Answer the following questions in detail., , 1., , Main causes of air pollution—, , (i) Smoke from vehicles and factories., , (ii) Burning of fossil fuels., , (iii) Farming chemicals., , (iv) Household products., , Main causes of water pollution, (i) Detergents and soap used in washing clothes, pollute water., , (ii) Uses of chemicals in agriculture also pollute water., , (iii) Bathing of cattle in ponds and lakes., , Smoke makes the air dirty and unfit for breathing. So smoke is harmful to us., Three ways to control air pollution—, , (i) Avoid burning leaves and other materials., , (ii), Reduce to use wood stove., , (iii) Use alternate fuels like biogas or less polluting fuels like CNG, PNG., Biodegradable waste is a substance that is capable of being decomposed naturally. E.g., Fruits, and vegetable peels., , F._ Name the following., , i., 2., a, 4., , a. Vehicles b. Industries c. Chemicals, a. Sewage b. Agriculture c. Cattle, a. Biogas b. CNG c. PNG, a. Coal b. Petrol c. Diesel, , G. Match the following., 1. (c) 2. (a) 3. (d) 4. (b), , H. Find the names of four pollutants in the following grid. Write their names in the blanks., 1.Plastic 2. Detergent 3. Soap 4, Methane