What specific type of physical weathering is dominant on beaches?

Cultural convergence is the theory that two cultures will be more and more like each other a very notable example of this is around the u.s.-mexico border, where 

Iam pretty sure it is c. 2000 bce

Here is a picture  of the net. its 4 squares in a row diagonal and on the third draw one square aove and under

Ibelieve it is- a mixed economy offers some protection for consumer rights but still allows a good deal of choice.