Heath and pressure manage to move the material between the bottom and top part of the mantle, causing currents, and affecting the surface of Earth.
Explanation:
The heat and the pressure are crucial for the cycling of matter on our planet. This process happens in the mantle layer. The lower part of the mantle is hotter because of the higher influence by the core, while the upper part is not as hot (though very hot for surface standards). This causes the material in the upper part to be more solid and denser, which in turn causes it to sink toward the bottom. As this material sinks the hotter and less dense one from the bottom is pushed upward. This creates the convection currents.
As the material from the bottom moves upward it comes in contact with the lithosphere. It puts a lot of pressure on it and supported by the heat manages to crack it, which created the tectonic plates. Because of the constant pressure the tectonic plates are pushed and moved on the surface of Earth. On some places (subduction zones) the crust from the surface sinks into the mantle, while from the mantle we have rise of magma toward the surface, so the material is constantly circling and being recycled.
