Question

Which phrase provides the best definition of mass movement?

the movement of material caused by erosion
the slow flow of a glacier as it moves through the valley of a mountain
the movement of large amounts of soil and rock debris down a slope
the fast movement of a boulder rolling down a slope

Answer 1

"the movement of large amounts of soil and rock debris down a slope"

Reason: Mass movement (mass wasting) is gravity-driven downslope movement of earth materials like soil and rock, including landslides, slumps, and debris flows.