How does vegetation affect mass movement?

Vegetation plays a significant role in mass movement, particularly in stabilizing the soil. When plants grow, their roots dig into the soil and rock layers, which helps to bind these materials together. This binding effect stabilizes the soil, making it less susceptible to erosion and mass movement, such as landslides or slumps. The root systems not only help to hold the soil in place but also promote the development of a healthy soil structure that can absorb and retain water, reducing the likelihood of saturation that might lead to slope failure.

In contrast, the other options suggest either no impact or a negative effect of vegetation on mass movement, which does not align with the established understanding of how plant life interacts with soil stability. Vegetation typically serves to slow down mass movement rather than accelerate it or have no impact at all.