The layer of the Earth that has convection currents that cause tectonic plates to move is the mantle.

Here's why:

* The Mantle's Composition: The mantle is a thick layer of hot, dense rock that sits beneath the Earth's crust.

* Convection Currents: Heat from the Earth's core causes the mantle to heat up. This hot rock rises, while cooler, denser rock sinks, creating a cycle of convection currents.

* Tectonic Plate Movement: The convection currents in the mantle exert a drag on the tectonic plates that sit on the Earth's surface. This drag causes the plates to move slowly over time, leading to phenomena like earthquakes, volcanic eruptions, and mountain formation.

Let me know if you'd like more details on any of these points!