According to the plate tectonic theory, the Earth's lithosphere (the rigid outer layer of the Earth) is made up of tectonic plates. These plates are not fixed, but are constantly moving and interacting with each other.

Here's a breakdown:

* Lithosphere: This is the rigid outer layer of the Earth, composed of the crust and the uppermost mantle.

* Tectonic plates: These are large segments of the lithosphere that move independently of one another.

* Types of tectonic plates:

* Continental plates: Composed primarily of granite, which is lighter and less dense than oceanic crust.

* Oceanic plates: Composed primarily of basalt, which is denser and thinner than continental crust.

Therefore, a tectonic plate can be made up of either continental crust, oceanic crust, or a combination of both.

Here's an analogy: Imagine a puzzle where each piece is a tectonic plate. The puzzle pieces move slowly, sometimes bumping into each other, causing earthquakes, volcanic eruptions, and mountain formation.