Core: Innermost layer, about 3476km wide all round, consists largely of iron and nickel, divisible into inner and outer core, found in a molten state, reservoir of minerals to the other zones.
Mantle: middle layer, surrounds the core, about 2897km thick, composed of very dense rocks, rocks are rich in olivine basalt.
Crust: Lies above the mantle, outer layer, consists of granitic and basaltic rocks, varies in thickness from place to place , divisible into 2-sial and sima, forms soil, sustains life.