(A) Sial and Sima
(B) Lithosphere and outer mantle
(C) Outer mantle and inner mantle
(D) Inner mantle and the core
»Important Links:
Online Test Preparation and Mcqs Website.
(A) Sial and Sima
(B) Lithosphere and outer mantle
(C) Outer mantle and inner mantle
(D) Inner mantle and the core