The upper part of the mantle upon which the crust of Earth floats is called ________.
-
mesosphere
-
barysphere
-
asthenosphere
-
none of these
C
Correct answer
Explanation
The asthenosphere is the ductile, highly viscous layer of the upper mantle on which the lithospheric plates float. It extends from about 100-330 km depth. Its plasticity allows tectonic plates to move. The mesosphere is the lower mantle, barysphere is another term for the Earth's core, and these terms help us understand Earth's internal structure.