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:

Wave erosion involves the back - and - forth movement of water. This movement acts like a mechanical force. When waves move back and forth along the coastline, they exert pressure on sediment and rock. Over time, this repeated action loosens the sediment and rock. Option B is more about deposition rather than erosion. Option C is incorrect as continuous impacts of waves erode (break down) rather than build up sediment and rock. Option D describes wind - related sediment transport (like in deserts or windy coastal areas where wind is the main agent), not wave - related erosion.

Answer:

Back - and - forth movement loosens sediment and rock.