The earth is composed of three different chemical layers: core, mantle and crust. the formation of these layers was from a process called

layering process

Explanation:

After the Earth was formed, it started to experience changes in its internal structure. This was caused by the different materials and their density and mas. The heavier materials started to sink deeper into the Earth, the ones with medium mas went in the middle, while the lightest ones remained at the top. This process is called layering, and it was the process that created the three basic layers of the Earth, core, mantle, and crust. The layering though was not perfect, so materials of all three types can be found in each of the layers, though there are dominants ones that define them, and the others in a much lesser amount.