Final answer:
The scenario that would be least likely to produce a mass wasting event is gradual vegetation growth stabilizing a previously bare hillside.
Step-by-step explanation:
The correct option is C:
The scenario that would be least likely to produce a mass wasting event is c) Gradual vegetation growth stabilizing a previously bare hillside. Mass wasting refers to the movement of rock, soil, and debris down slopes under the influence of gravity. In the given scenarios, a heavy rainfall saturating loose soil on a steep slope (a), an earthquake causing the destabilization of a cliff face (b), and construction activities altering the angle of repose on a slope (d) can all increase the likelihood of a mass wasting event.
Human activities, such as construction, can also alter the slope's angle of repose and contribute to its instability. Conversely, gradual vegetation growth can help stabilize slopes by binding the soil together with roots, making it more resistant to erosion and less prone to mass wasting.However, gradual vegetation growth (c) can have a stabilizing effect on slopes. The roots of plants help bind the soil together, reducing the risk of slope failure.