Answer:
The answer is The mantle
Step-by-step explanation:
The asthenosphere (from the Greek word asthenēs meaning “weak”) is a mechanically weak layer consisting of the lower portion of the upper mantle, extending down to 660 km. Contrary to popular belief, it is not a “sea of molten rock”. The upper mantle is actually composed of an Mg- and Fe-rich rock called peridotite.