The earth consists of three concentric layers namely Crust, Mantle, and Core. Below is the description of each layer individually.
1. Crust = It is the outer layer of the earth. It is a thin layer between 0-60 km thick. The crust is the solid rock layer upon which we live.
2. Mantle = It is the widest section of the Earth. It has a thickness of approximately 2,900 km. The mantle is made up of semi-molten rock called magma. In the upper parts of the mantle, the rock is hard, but lower down the rock is soft and beginning to melt.
3. Core = It is in the center and is the hottest part of the Earth. It consists of two parts namely the inner core (made up of iron, steel etc) and the outer core (liquid layer).
The figure below shows the labelled diagram of the structure of the earth: