Chapter - Review:
- The surface of the Earth is not the same everywher.
- The earth has an infinite variety of landforms. Some parts of the lithosphere may be rugged and some flat.
- landform are a result of two processes. The 'internal process' leads to the upliftment and sinking of the Earth's surface. Second, external process is the continuous wearing down and rebuilding of the land surface.
- the wearing away to the earth's surface is called 'erosion'. The surface is being lowered by the process of erosion and rebulit by the process of 'deposition'.
- These two processes, that is, erosion and deposition are carried out by running water, ice and wind.
- Mountain is natural elevation of the earth surface. The mountains may have a small peak and a borad base.
- In some mountains, there are permanemtly frozen rivers of ice. They are called 'glaciers'.
- Less people live in the mountain areas because of harsh climate.
- Less land is available for farming because slopes are steep.
- Mountains arranged in a line is known as range.
- mountains arranged in a line is known as range.
- Mountains vary in their heights and shape.
There are three types of mountains:
1. Fold Mountains
2. Block Mountains
3. the volcanic Mountains
- Fold mountains are formed due to the processes of erosion.
- Block mountains are created when large area are broken and displace vertically. the uplifted blocks are termed as 'horsts' and lower blocks are called 'garben'.
- Volcanis mountains are formed due to volcanic activity.
- A plateau is an elevated flat land. It is flat - topped table land standing above the surrounding area. a plateau may have one sides with steep. These may be young or old, hundred metres to several thousand metres.
- Most of the planis are formed by rivers ahnd their tributaries. some o the largest plains made by the rivers are found in asia and North America.
- Generally, the plains are very fertile, easy to transport. Thus, these are thickly populated regions of the world.
- In Asia, Plains are formed by the Ganga and the brahmaputra in India and the Yangtze in chaina.
- Plains areas are useful for habitation.
