Here's why:

* Lithosphere: The lithosphere is the rigid outermost layer of the Earth, composed of the crust and the uppermost part of the mantle.

* Continental Crust: This is the thicker, less dense crust that makes up the continents.

* Oceanic Crust: This is the thinner, denser crust that forms the ocean floor.

Therefore, lithospheric plates are made up of both types of crust, along with the upper mantle. These plates move independently on the asthenosphere, the partially molten layer beneath the lithosphere.