Which of the following explains how heat flow within earth changes its surface? molten material moves in one direction, moving the plates in the opposite direction molten material moves in one direction, moving the plates in the same direction cyclical movement of molten material moves plates in different directions cyclical movement of molten material moves all plates in one direction

The appropriate answer is C. Cyclical movement of molten material moves the plates in different directions. The cyclical movement refers to convection current in the mantle that are driven by heat from the earth's core. The heat from the core heats the the layer of the mantle closest to it. This layer is now less dense than its surroundings which forces it to rise. Once this rising plume reaches the base of the crust it cools and now becomes more dense than surrounding layers so it sinks. 

These continuous convection currents cause the crustal plates to converge, diverge or slide past each other in opposite directions.