Question

why are there valleys and gorges along the river​

Answer 1

Answer:

VALLEYS AND GORGES

High in the mountains, the river is narrow and fast-flowing. Mountains are steep, so the river flows downhill very quickly. Its water carries pebbles and boulders that erode (wear away) the sides and bottom of the river bed, deepening the river and cutting down the mountain in a V-shape, called a valley. Most of the valley-cutting takes place when the river is flooded. Many mountain rivers flood regularly as a result of seasonal changes like melting snow or heavy rainfall. Sometimes, instead of forming a V-shaped valley, rivers create dramatic, steep-sided gorges. This happens when the river is running down a landscape that is slowly being pushed upward by plates moving under the Earth’s surface.