Final answer:
Erosion is the removal of surface material by the action of particles. It is an important geological process that shapes the Earth's surface.
Step-by-step explanation:
The removal of surface material by the action of numerous individual impacts of solid or liquid particles is called erosion. Erosion is a key geological process that helps shape the Earth's surface over time. One example of erosion is the wearing away of rocks by flowing water in rivers, which can create valleys and cliffs.