Which term describes the rigid outer layer of Earth including crust and uppermost mantle?

Which term describes the rigid outer layer of Earth including crust and uppermost mantle?

• A. Mantle
• B. Crust
• C. Asthenosphere
• D. Lithosphere

Answer: (D)

The main idea is that Earth’s outer shell is a rigid layer made up of both the crust and the rigid portion of the upper mantle. This combined, rigid shell is called the lithosphere. It behaves as a brittle, strong shell that forms the tectonic plates. Below it lies the asthenosphere, which is more ductile and allows the plates to move. The mantle alone is a much larger region, and the crust alone is only the very outermost skin. So the term for the rigid outer layer including crust and uppermost mantle is lithosphere.

The main idea is that Earth’s outer shell is a rigid layer made up of both the crust and the rigid portion of the upper mantle. This combined, rigid shell is called the lithosphere. It behaves as a brittle, strong shell that forms the tectonic plates. Below it lies the asthenosphere, which is more ductile and allows the plates to move. The mantle alone is a much larger region, and the crust alone is only the very outermost skin. So the term for the rigid outer layer including crust and uppermost mantle is lithosphere.