Answer:
motion... tectonic
Explanation:
The convection currents in the mantle are a process of motion that creates circular movement of the material in the mantle. It works in a very simple way. The lower part is hotter, while the upper part is cooler, so the material in the lower part heats up and because it is lighter it moves upward, while the cooler and denser material fro the upper part falls downward. This motion where there is movement of hot and molten rock, plus the high pressure, managed to crack the lithosphere and create numerous tectonic plates. The plates move because there is constant pressure on them from the convection currents from below, and while the movement may seem slow, on the long run it creates lot of changes on the planet.
