Which layer includes the crust and the uppermost mantle?

The layer that includes the crust and the uppermost mantle is the lithosphere. This layer is characterized by its rigid and solid properties, which result from the cooler temperatures found at the surface of the Earth. The lithosphere extends from the Earth's surface down to approximately 100 kilometers (62 miles) below, encompassing both the continental and oceanic crust as well as the uppermost part of the mantle, which behaves more like a solid than a fluid.

Understanding the composition of the lithosphere is crucial for grasping various geological processes, such as tectonic movements, which are responsible for earthquakes, volcanic activity, and the formation of mountains. The distinction of the lithosphere from the underlying asthenosphere, which is the layer directly beneath it and behaves more like a plastic that can flow, further highlights its role as a rigid outer shell of the Earth. In contrast, the core and mantle options refer to different layers that do not include the crust.