Page 332 - New Medley 5 Semester 1

the mountains and deposit them in the plains. Such plain areas have very

fertile soils, which are good for crops.

The plain areas are thickly populated. Many cities and towns have come

up in plain areas. Some plains are located in the interior of continents,
while many others are along the sea coast.

The plain areas are more important than the mountains and plateaus.
They have the following benefits for us:

1. Plains in the river valleys have fertile soils and are thus useful for
growing a large variety of crops.

2. Plains are also useful for developing irrigation facilities, industries
and various means of transport.

• Critical thinking
Cross () the wrong statements.
1. The Himalayas are young mountains.

2. Rockies in North America are a vast plain land.

3. The Plateau of Tibet is surrounded by water on all sides.

4. The plain areas are thickly populated.

River Valleys

As it rains on the mountains, a large part of
the rainwater flows as small streams. Many

other streams join together to form rivers. The
rivers can cut the rocks and make a valley for Upper Course

themselves. The river generally has three stages.

1. The upper or the young course in the Middle Course

mountains
2. The middle or the mature course in the plains
Lower
3. The lower or the old course, when the river Course

falls into the sea or ocean.

Courses of a river

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