How many layers our there on Earth?

There are four layers on Earth. These layers are the crust, mantle, outer core, and inner core. The crust is the outermost layer and is made up of solid rock. The mantle is beneath the crust and is composed of semi-solid rock. The outer core is a liquid layer made of molten iron and nickel. Finally, the inner core is the solid center of the Earth, consisting of iron and nickel.