Which description best defines the lithosphere?

Which description best defines the lithosphere?

• A. It is composed mainly of iron
• B. It is a liquid layer beneath the mantle
• C. It is the deepest layer of Earth
• D. It includes the crust and upper mantle and forms tectonic plates

Answer: (D)

The lithosphere is the Earth's outer, rigid shell made up of the crust and the upper part of the mantle. It forms the tectonic plates that float and move on the partially molten layer beneath called the asthenosphere. It’s not mainly iron—that description would fit the deeper core—and it’s not a liquid layer or the deepest part of Earth. The key idea is that the lithosphere combines crust and upper mantle and creates the tectonic plates that drive plate tectonics.

The lithosphere is the Earth's outer, rigid shell made up of the crust and the upper part of the mantle. It forms the tectonic plates that float and move on the partially molten layer beneath called the asthenosphere. It’s not mainly iron—that description would fit the deeper core—and it’s not a liquid layer or the deepest part of Earth. The key idea is that the lithosphere combines crust and upper mantle and creates the tectonic plates that drive plate tectonics.