Which process breaks material down in place?

• A. Deposition
• B. Sedimentation
• C. Weathering
• D. Erosion

Answer: (C)

Weathering breaks material down in place. It wears away and dissolves rock and other parent materials where they sit, rather than removing them from the site. This breakdown can be physical, like freeze–thaw splitting, thermal expansion, or abrasion, or chemical, such as reactions with water, acids, or other chemicals that loosen minerals. As weathering proceeds, it shatters and alters the material, helping to form soil by increasing surface area and releasing nutrients from the parent material.

This is different from erosion, which involves moving soil or rock away from the original site by wind, water, or gravity; and from deposition, which is the laying down of transported material in a new place after it has been moved. Since the defining feature of weathering is in-place breakdown, it is the process described here.