The layer of Earth that contains both the crust and upper mantle is called the lithosphere.

Here's why:

* Crust: The outermost layer of Earth, relatively thin and composed of various rock types.

* Upper Mantle: The layer beneath the crust, extending down to about 410 kilometers (255 miles).

* Lithosphere: A rigid, outermost layer of Earth that includes the crust and the uppermost part of the mantle. It's essentially a "shell" that behaves as a single, solid unit.

Think of the lithosphere like a giant, cracked eggshell. The individual pieces of this shell are called tectonic plates, which move and interact with each other, leading to phenomena like earthquakes, volcanoes, and mountain building.