According to the theory of ____, molten rock emanates from the edge of a plate on the Earth's crust, pushing rock on the other side into a trench.

A) uniformity
B) plate tectonics
C) hot spots
D) fault line rupture
E) biogeography

The theory of plate tectonics explains how the Earth's crust is composed of plates that move and collide with each other. At certain boundaries, molten rock from the mantle rises up and pushes the plates apart or causes them to collide and be pushed underneath one another, forming trenches.