Answer:
The third layer is the Outer Core
Step-by-step explanation:
The first layer is called the Crust and it is the thinnest layer of the Earth. The second is the Mantle and it is the thickest layer of earth's crust, it's divided into two parts but the mantle is made up into one. The third layer is the Outer Core and the Outer Core is made up by composed iron and liquid.