normal faulting seafloor spreading igneous intrusions convection currents
I gave my students this multiple choice question: The surface of Earth is composed of large tectonic plates that are constantly shifting as they float on top of molten rock. Which process must occur in the mantle to make the plates move?

Only one answer is correct among these 4 choices:
- normal faulting
- seafloor spreading
- igneous intrusions
- convection currents

Could you tell me which one is correct?

convection currents