Fact 1: The surface of a beach is formed by mechanical weathering.

Fact 2: Water is a mechanical weathering force.

Given the two facts above, answer the question "what is the surface of a beach formed by?" with the following options: 
- a wave
 - gravity
 - water
 - plates
 - density
 - the sun
 - calcite
 - Rocks


 

   water      