The document describes the different layers that make up the interior of the Earth. It is divided into four main layers from outermost to innermost: the crust, mantle, outer core, and inner core. The crust is the thinnest layer and is made up of either oceanic or continental crust. Below the crust is the mantle, which is the largest layer and makes up most of the Earth's volume. At the center are the outer core, made of liquid iron and nickel, and the solid inner core, also made of iron and nickel.

22. What do you know about these layers?