The surface of a beach is formed by mechanical weathering, and most beaches are of white coral sand. Given these facts, what action produces much of the sand from coral among the following options:
- reef building
 - radioactive decay
 - mechanical waves
 - glass blowing
 - It used to be covered by water
 - The area was once underwater
 - Mechanical weathering
 - By coral exoskeletons


 

       Mechanical weathering  