Which sentence best describes mass movement?
a. The movement of people from New Jersey to Ohio
b. The downhill flow of soil and rock resulting from gravity
c. The steady pace of air bouncing off a mountain
d. The downhill movement of animals due to heavy snow in their normal home
B is correct. Mass movement is the movement of surface material due to the force of gravity (along with geological agents). Examples are landslides and rockfalls.
