The outer layer of earth is least dense. Explain WHY

The densest layer is the solid metal inner core,

Explanation:

The inner core is a hot, dense ball of (mostly) iron. It has a radius of about 1,220 kilometres (758 miles). ... The inner core's intense pressure—the entire rest of the planet and its atmosphere—prevents the iron from melting. The pressure and density are simply too great for the iron atoms to move into a liquid state.

answer; ///i believe the answer is ( a hitch and signals);