Which process involves rock material being rolled along a river bed or beach?

Which process involves rock material being rolled along a river bed or beach?

• A. Traction
• B. Suspension
• C. Transport
• D. Transpiration

Answer: (A)

Traction is about sediment that is too large to be carried up into the water column, so it stays in contact with the bed and is rolled or dragged along by the current or waves. This rolling of rocks and pebbles along the riverbed or beach is the hallmark of traction, which happens when the flow has enough energy to overcome friction with the bed. In contrast, suspension involves tiny particles being carried within the water, not rolling on the surface, and transport is a broad term for any movement of sediment, not the specific rolling action. Transpiration is irrelevant here, as it refers to water movement in plants.

Traction is about sediment that is too large to be carried up into the water column, so it stays in contact with the bed and is rolled or dragged along by the current or waves. This rolling of rocks and pebbles along the riverbed or beach is the hallmark of traction, which happens when the flow has enough energy to overcome friction with the bed. In contrast, suspension involves tiny particles being carried within the water, not rolling on the surface, and transport is a broad term for any movement of sediment, not the specific rolling action. Transpiration is irrelevant here, as it refers to water movement in plants.