The development:
(i)The earth was mostly in a volatile state during its primordial stage. Due to gradual increase in density the temperature inside has increased. As a result the material inside started getting separated depending on their densities.
(ii)This allowed heavier materials to sink towards the centre of the earth and the lighter ones to move towards the surface.
(iii)With passage of time it cooled further and solidified and condensed into a smaller size. This later led to the development of the outer surface in the form of a crust.
(iv)During the formation of the moon, due to the giant impact, the earth was further heated up.
(v)It is through the process of differentiation that the earth forming material got separated into different layers.
