What is the term for the rigid mantle layer situated below the asthenosphere?

What is the term for the rigid mantle layer situated below the asthenosphere?

• A. Lower Mantle
• B. Mantle
• C. Core
• D. Lithosphere

Answer: (A)

The main idea is how Earth’s interior is layered by rigidity. The asthenosphere is part of the upper mantle and is relatively ductile, letting the tectonic plates move. Directly below that lies a much more rigid region—the lower mantle—which extends down to the outer core. So the rigid mantle layer beneath the asthenosphere is called the lower mantle. The lithosphere is the rigid shell above the asthenosphere (crust plus the very upper mantle), the mantle as a whole includes both upper and lower parts, and the core lies beneath the mantle.

The main idea is how Earth’s interior is layered by rigidity. The asthenosphere is part of the upper mantle and is relatively ductile, letting the tectonic plates move. Directly below that lies a much more rigid region—the lower mantle—which extends down to the outer core. So the rigid mantle layer beneath the asthenosphere is called the lower mantle. The lithosphere is the rigid shell above the asthenosphere (crust plus the very upper mantle), the mantle as a whole includes both upper and lower parts, and the core lies beneath the mantle.