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11.Air,Water and Weather, Exercises, A. Choose the correct answers,, 1. Nitrogen gas is present in the maximum amount in the atmosphere., 2. When the wind blows gently, we call it a breeze., 3. The rainy season is also known as the monsoon., 4. On rainy days, we wear raincoats., 5. Water exists in three forms., B. Write T for true or F for false., 1. Fifty per cent of our body is made of water., False, 2. When the clouds become too heavy, they fall as rain., True, 3. Autumn comes after winter., False, 4. Water vapour is light and rises., True, C. Fill in the blanks., 1.The layer of air surrounding us is called atmosphere., 2. The falling of rain, snow or hail is called precipitation., 3. The season before summer is called spring., 4. 71 percent of the Earth's surface is made of water., 5.Autumn is the season in which trees shed their leaves., D. Give two examples of each., 1. Gases present in the atmosphere, Nitrogen, Oxygen, 2. Things that cause smoke to form in the air, Chimney ,Car, 3. Things you would like to do on a sunny day, Swimming , Eating ice-cream, E. Answer these questions in brief., 1. Name the major gases that make up the atmosphere., Ans-Nitrogen, Oxygen and Carbon di oxide, 2. What is a water cycle?, Abs-The process of evaporation,condensation and precipitation goes on in nature like a cycle is called the water cycle., 3. On what factors does the weather of a place depend?, Ans- Weather depends on the sun,wind,water vapour,clouds and rain., F. Answer these questions in detail., 1. Write the various ways in which air is useful to us., Ans-Uses of Air, All living things need air to breathe., Air is needed for burning., It helps things to move, it also helps to aeroplanes to fly,boats to sail and clothes to dry., 2. How are clouds formed?, Ans-Water from oceans, rivers and other sources evaporates into air as water vapour.It cools down on coming in contact with the cool air and changes into tiny droplets of water to form clouds.