Geography
Assertion (A): In the upper course the dominant activity of a river is erosion.
Reason (R): The river flows swiftly as the gradient is steep.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R does not explain A.
- A is true but R is false.
- A is false but R is true.
Answer
Both A and R are true and R is the correct explanation of A.
Explanation — The upper course of a river generally lies in a hilly area and the river flows a considerable distance over a steep slope. Along its course, it erodes its bed and banks; and carries large boulders of rock with it. Under the impact of rush of water and the load the river carries, erosion action is swift and effective.
Related Questions
The displacement of rocks by agents like wind, water or ice:
- Deposition
- Transportation
- Erosion
- Mass wasting
The large-scale movement of loose materials (rock-waste) down the slope on account of gravity:
- Mass movement
- Deposition
- Denudation
- Weathering
The laying down of material that has been weathered, eroded and transported by natural processes such as water, wind and ice.
- Physical Weathering
- Deposition
- Denudation
- Tributary
The streams or small rivers which join the main river are called:
- Transporteries
- Tributaries
- Distributaries
- Meanders