The layer of the Earth that makes up the plates is the lithosphere. The lithosphere is the rigid outermost layer of the Earth, composed of the crust and the uppermost part of the mantle.

Continents are sliding on the asthenosphere, which is a semi-molten layer beneath the lithosphere. The asthenosphere is not completely liquid but behaves like a very viscous fluid, allowing the lithospheric plates to move on top of it.

Here's a simplified explanation:

* Imagine the Earth like a hard-boiled egg. The shell is the lithosphere, which is broken into pieces like a cracked shell.

* The egg white represents the asthenosphere, a layer of partially molten rock.

* The yolk represents the Earth's core.

The plates of the lithosphere move slowly over the asthenosphere due to convection currents within the Earth's mantle. This movement is responsible for the formation of mountains, volcanoes, and earthquakes.