Here's a breakdown:

* Lithosphere: This is the rigid outermost layer of the Earth. It's made up of the crust and the uppermost part of the mantle. Imagine it like a giant, cracked eggshell.

* Asthenosphere: This is the layer beneath the lithosphere. It's hot, partially molten, and acts like a very viscous fluid.

The lithosphere is broken into several large and small pieces called tectonic plates. These plates are constantly moving, interacting with each other in various ways:

* Convergent boundaries: Plates collide, leading to mountains, volcanoes, and earthquakes.

* Divergent boundaries: Plates move apart, creating new ocean floor and rift valleys.

* Transform boundaries: Plates slide past each other horizontally, causing earthquakes.

So, while the Earth's mantle is the driving force behind plate movement (due to convection currents), it's the lithosphere itself, made up of those tectonic plates, that's actually moving on top of it.