Answer:
the inner core if I believe. I apologize if I am incorrect
Answer:3.51
Explanation:
Given
Coefficient of Friction 
Consider a small element at an angle \theta having an angle of 
Normal Force

Friction 

and 







The lithosphere is one of the four layers of the earth's interior. The lithosphere is the layer above the mantle of the earth and is the topmost part. Lithosphere includes a part of the mantle and the continental and oceanic crust.