Answer:
There are three main ways in which the coast can be eroded by the sea:
Hydraulic action: lots of sea water crashes against the land, causing air and water to become trapped and compressed in surface cracks. When the sea retreats the air expands, weakening the cracks in the rock and causing pieces of the rock to break off.
Corrasion: caused by bits of rock hitting the cliffs and other parts of the land, causing more bits of rock to break off.
Corrosion: involves the chemical action of sea on rock, often happens with limestone beaches, when the limestone dissolves in the sea water although the salt can affect some other stones as well.
Step-by-step explanation: