Answer: Erosion
The process in which there is a wearing down on the surface on the earth which goes through the erosion is called gradation.
Step-by-step explanation:
There is a certain force which is the cause for the formation of earth’s surface and that force is called as endogenic forces.
There may come up a question about how the surface of the earth is not even, the reason is due to exogenic process failing to even out the variation of the land.