Final answer:
The underlying force that drives plate tectonics is convection currents. Convection currents are caused by the heat generated within the Earth's mantle, which creates a circular motion and pushes the tectonic plates.
Step-by-step explanation:
The underlying force that drives plate tectonics is convection currents. Convection currents are caused by the heat generated within the Earth's mantle. As the mantle heats up, it becomes less dense and starts to rise, while the cooler, denser material sinks towards the core.
This movement creates a circular motion, similar to the boiling of a pot of soup. This convection creates the force that pushes and moves the tectonic plates, causing them to interact, collide, or separate.
For example, at divergent plate boundaries, where two plates are moving apart, the rising convection currents create tension and cause the plates to separate. At convergent boundaries, where two plates collide, the sinking convection currents create compression and force the plates to collide and form mountains or cause earthquakes.
Learn more about Plate tectonics