Answer: False
Explanation:
The asthenosphere constitutes to about 180 km of the total mantle which is almost 2900 km. As compared to asthenosphere the total area covered is very less.
It cannot be said that it covers a large area of mantle. The asthenosphere is the highly viscous but mechanically weak and ductile region which lies in the upper part of the mantle.
It lies just below the lithosphere in between 80 to 200 km below the surface.