Question

River banks have sand only in their lower courses in the plains. You would find it difficult to find sand along the banks of a river in mountains and hills. Why is this so?

• A. Water moves slower in the plains than in mountains
• B. Water moves faster in the plains than in mountains
• C. Water has more oxygen in the mountains than in the plains
• D. Water in the mountains does not contain sand

Answer 1

The correct option is A

Water moves slower in the plains than in mountains

As rivers flow from the mountains to the plains, the water slows down. This is because the steepness of the land they flow on decreases as the river makes its way into plains. This slower water is unable to hold on to the sand it carries from the mountains. Thus, it settles down here along the banks.

The fast moving water in the mountains causes more mixing and allows sand to be suspended in water.