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Fill in the blanks with appropriate words., (a) Mt Everest, , (b) silt, sand, clay, , (c) tectonic
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(d) lava plateau, , (e) graben, , - Choose the correct answer., (a) (i) (b) (i) ©) @, (d) (ii) (e) @), , . Match the rows., (a) (¥), (6) (i), (c) (ii) (A) Gi) (e) Gv), , . Write true or false. Correct the false sentences, in your notebook., , (a) True, , (b) True, , () False. Plains are most suitable for human, settlement., , (d) False. The Aravalli Mountains are old fold, mountains., , (e) True, , . Answer the following questions in one or two, sentences., , (a) A fold mountain is a raised portion of the, earth’s surface caused by the compression, of the layers of the earth from both sides., These generally have long parallel ranges,, for example, the Rockies and Andes., , (b) Block mountains are formed due to faulting, and uplifting. Volcanic mountains are, generally formed by the deposition of molten, material that comes out from below the, surface of the earth, , (c) Plateaus are elevated regions, lower than, mountains, which have a flat top and steep, sides., , (d) Plains are generally formed by the deposition, of alluvium brought down by rivers and, deposited in low-lying areas,, , (e) Plains are fertile because of the alluvial soil, and plenty of water for agriculture. This is, also the reason why a large number of people, inhabit the plains, , 6. Answer the following questions in four or five, , sentences., , (a) Fold mountains are formed due to the, compression (pressure from both sides) of, horizontal layers of rocks. A simple fold, mountain has ‘down folds’ or valleys called
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syncline and ‘up folds’ or ridges called, anticlines. Block mountains are formed due, to tension (opposite of compression) that, Creates faults (cracks) in the crust. The land, between the cracks is uplifted by internal, forces §enerating within the earth to forma, block mountain or horst., , (b) Volcanic mountains are formed by deposition, of molten material called lava from beneath, the crust. This happens due to internal, earth movements which pushes the molten, material to the surface through openings, oF vents in the crust. The molten material, gradually piles up and cools layer after layer, Over the years to form a conical mountain., Mt Vesuvius (Italy) is a famous volcanic, Mountain. (Refer to page 152 of the textbook, for the diagram.), , (c) A rift valley is formed due to tension that, creates faults in the crust. The area between, two parallel faults or cracks sinks down, forming a rift valley. A rift valley is also called, a graben. The largest rift valley in the world, is the Great Rift Valley in East Africa, which, is about 6,000 km in length. The Narmada, Valley in India is a very good example of a, , rift valley., , (d) A plain is a low-lying, flat land surface not, more than 200 m above sea level. Plains are, generally formed by deposition of alluvium, washed down from mountains and plateaus, by rivers. The Indo-Gangetic Plain of India, is world famous. Plains generally have high, , population densities as agriculture is possible, in plains., , a plateau is generally lower in height than, a whe mountain has high pointed, peaks and alleys whereas a plateau is, generally flat. This is i, , ated are sparsely, populated as théy are not Suitable for, farming, afrd the climate is also harsh while
