Question

wind, water, and ice breaking down rock is called
deposition
erosion
compaction
weathering

Explanation:

Weathering is the process where wind, water, and ice break down rocks. Erosion involves the movement of these weathered materials. Deposition is the laying down of eroded materials. Compaction is related to the compression of sediments (usually in sedimentary rock formation). Since the question is about breaking down rock (not moving or depositing materials), weathering is the correct term.

Answer:

Weathering