What are the features of each of the three compositional layers of earth?

There is the main core theres 2 as for mantel and 3 crust

Earth can be divided into three main layers: the core, the mantle and the crust. Each of these layers can be further divided into two parts: the inner and outer core, the upper and lower mantle and the continental and oceanic crust. Both the inner and outer core are made up of mostly iron and a little bit of nickel.