Question

What process causes most of the erosion on earth

Answer 1

water. glaciers create a massive amount of erosion as well, but after all, a glacier is made out of water.
seriously though, it's still water

Answer 2

Erosion is the process by which the surface of the Earth gets worn down. Erosion can be caused by natural elements such as wind and glacial ice. But anyone who has ever seen a picture of the Grand Canyon knows that nothing beats the slow steady movement of water when it comes to changing the Earth.