Answer:

1: The Indian desert lies towards the Western margins of the Aravali Hills . It is an undulating Sandy PLANE covered with sand dunes. This region receives very low rainfall below 150 mm per year .It has arid climate with low vegetation cover. streams appear during the rainy Seasons. soon after they disappear into the sand as they do not have enough water to reach the sea .Luni is the only large river in this region.

2:

• The Himalayas extend from the Indus in the west to the Brahmaputra in the East.
• The length of the Himalayas is about 2400 KM.
• Its width varies from 400 kilometre in the west to 150 km in the East.
• the height of the mountain in the Eastern HALF is greater than that in the Western half

3: The oldest land mass was a part of gondwanaland. The gondwanaland include India, AUSTRALIA ,South Africa ,South America and Antarctica is one single land mass. the convectional current splits the crust into a number of Pieces thus leading to the drifting to the Indo Australian iron plate after being separated from the gondwanaland towards north. the northward drifted RESULTS in the collision of the plate with the much larger Eurasian plate. due to this collision the sedimentary rocks which were accumulated in the geosyncline known as the Tethys were folded to form the mountain system of Western Asia and Himalaya