Question

which word best describes the hot, weak, inner part of the upper mantle, which can flow?
○ crust
○ lithosphere
○ core
○ asthenosphere

Explanation:

To solve this, we analyze each option:

• Crust: The outermost layer of the Earth, solid and rigid, not the inner part of the upper mantle.
• Lithosphere: Consists of the crust and the rigid upper mantle, not the weak, flowable part.
• Core: The innermost layer of the Earth, not part of the mantle.
• Asthenosphere: Defined as the hot, weak, inner part of the upper mantle that can flow.

Answer:

asthenosphere (the option with "asthenosphere" text)