Question

In two or more complete sentences describe how a dam placed in a river can act as both a constructive and destructive force.

Answer 1

Dams are constructed over the narrow valleys and it acts like a barrier that obstructs the water from the flow. There are both advantages as well as disadvantages in constructing a dam.

Some of the constructive force or advantages of dams are as follows-

1) It generates electricity .

2) It is often used for irrigation and industrial purposes.

3) it is used for farming purposes in water such as raising as well as harvesting of fishes and other aquatic plants.

Some disadvantages are-

1) It degrades water quality.

2) Aquatic organisms are affected thereby harming the ecosystem.

3) It obstructs the flow of water.

4) Failure of a dam causes flood.

Answer 2

The good thing about a dam is that electricity can be created by mechanical means. That does not affect the atmosphere. Storing such production is a different matter.

The bad thing about a dam is that it wreaks havoc on the land where the water is stored behind the dam.