Mass wasting refers to

• A. the downslope movement of soil and rock due to gravity
• B. erosion by wind
• C. transport by water
• D. glacial transport

Answer: (A)

Mass wasting is the downslope movement of soil, regolith, and rock driven primarily by gravity. This includes events that range from slow creep to rapid landslides, rockfalls, debris flows, and mudflows—movements that occur along or parallel to slope surfaces with gravity as the main force, often aided by factors like water that reduce strength or add weight. Erosion by wind, transport by water, and glacial transport involve moving material through wind forces, water flow, or ice, respectively, rather than a gravity-driven downslope slide or fall. So the description that emphasizes gravity pulling material downslope correctly identifies mass wasting.