What is the agent acting on the sand?

How did the sandbar form?

The movement of the sediment by a river is caused by:

This dust storm shows the movement and dropping of sediment.

How was the cave formed?

The glacier moving across the rock and breaking it apart, is an example of:

What process gives the rock the reddish brown color?

What agent caused the mud to move down the hill?

Lichens secrete acids and break down the rock.

This is an example of: