What is an example of erosion in rocks?

• A. A rock moving through a river.
• B. A rock being broken down by wind.
• C. A rock melting into lava.
• D. A rock dissolving in water without movement.

Answer: (A)

Erosion is the process of wearing away rock and moving the material to a new location by natural forces. When a rock is carried along by a river, the flowing water transports it downstream, abrades it against other rocks, and gradually removes material from its surface. The key idea is movement and transport of rock, not just breakdown in place. If rock simply breaks apart due to wind without being moved, that’s weathering. If rock melts into lava or dissolves in water without being carried away, those are melting or dissolution, not erosion.