Question

According to the theory plate tectonics, the Earth's crust is broken into about 12 plates that float on hotter, softer rocks in the underlying mantle. These plates move about the Earth, just inches each year. These slight movements are responsible, in great part, for the earthquakes and volcanoes that happen on Earth. What is the source of energy that drives this plate movement?
A the subducton of the sea floor
B convection currents in the mantle
C the different densities of the oceanic and crustal plates
D the friction force between the plates that move past each other

Answer 1

B — convection currents in the mantle.

Mantle convection (hotter rock rising, cooler rock sinking) provides the main driving force for plate motions (with slab-pull and ridge-push as consequences of that convective circulation).