Question

which is one way that waves erode coastlines?
○ back-and-forth movement loosens sediment and rock.
○ large rocks are picked up and deposited in new areas.
○ continuous impacts build up sediment and rock.
○ loose sediment is picked up and blown to other locations.

Explanation:

To solve this, we analyze each option:

• Option 1: Waves' back - and - forth (swash and backwash) movement can loosen sediment and rock, which is a form of erosion.
• Option 2: Depositing large rocks is deposition, not erosion.
• Option 3: Building up sediment and rock is deposition, not erosion.
• Option 4: Sediment being blown (by wind, not waves) is wind erosion, not wave erosion.

So the correct option is the one about back - and - forth movement loosening sediment and rock.

Answer:

A. Back - and - forth movement loosens sediment and rock.