The Earth is composed of four main layers.  What are they?
user
The most famous four layers are the outer crust, inner mantle, outer core and inner core.
assistant
The Earth is composed of four main layers.  What are they?
user
I think you might mean geological “layers”, not “layers” as in “organization.”  You mean, what are the primary kinds of rock?
assistant
The Earth is composed of four main layers.  What are they?