Identify the underlying force behind all forms of mass movement

gravity

Explanation:

Mass movement or mass wasting is a natural process in which the unstable sediments, stones, pebbles, debris moves down the slope under the effect of gravity. These materials are disturbed by physical agents such as water, wind and others. The mass movement is responsible for mudslides or landslides.

its first and third is your answer i did the qustion the fourth isnt right