[fw.01]dams are used to produce hydroelectric power. which of these best describes the impact of a dam on the environment?

Out of the given statements, the statement that best describes the impact of a dam on the environment is that it causes changes in the river ecosystem.

Explanation:

Dams are usually built on rivers that flow through valleys formed by two elevated landforms on two sides. Thus, when a dam is built, it interferes with the natural setting and stops the natural flow of the water. This makes the water levels behind the dam grow considerably. Many a times, the landforms in the surrounding regions get submerged in the water due to the increased levels of water. The natural movement of aquatic animals like fishes and crabs is also hindered by the dam.