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Showing posts from December, 2017

Air

Air A1. Nitrogen & Oxygen 2. Oxygen 3. Carbondioxide 4.Photosynthesis 5.Ozone 6.Polluted air B.1.True 2.True 3.False 4.False 5. True. C.1.(b) Nitrogen   2,(c) smoke 3.(c) Water Vapour. 4.(d) Carbon dioxide 5.(b) Acid rain. D1.Name  the main components of air. Ans:The main components of air are nitrogen, oxygen, carbon dioxide &water vapour  . D2.State  the meaning of the term photosynthesis. Ans: Photo means light and synthesis means to combine. Photosynthesis is a process in which green plant prepare food  by combining water and carbon dioxide in presence  sunlight  and chlorophyll is called photosynthesis. D3.State two possible harmful effects of ultraviolet  rays. Ans: Two possible   harmful effects of Ultraviolet ray are: i)Skin cancer in human being. ii)Damage to the eye lenses of human being . d4.Define  the term  Air Pollutants. Ans:The Impurities present in air and are harmful to...