Crust 0-100 km thick Lithosphere (crust and upper- most solid mantle) Asthenosphere Mantle Mantle Crust 2,900 km Liquid Core Outer core 5,100 km Inner core Solid 6,378 km Not to scale 1. Name the layers that are defined by their physical state of matter. 2. Name the layers that are defined by their chemical composition. 3. What is the chemical composition of the Earth's innermost layer? 4. Which two layers are involved in the plate tectonic processes?