Which two layers of Earth are mainly composed of metallic elements such as nickel and iron, which are abundant in meteoroids and comets?

This layer of the earth lies between the mantle and the solid inner core. It is the only liquid layer, a sea of mostly iron and nickel about 1,400 miles. The lava is mostly made up of iron and nickel. The outer core creates the Earth's magnetic field. The final layer is the inner core, which is 900 miles deep. Scientists believe the inner core is a solid ball of iron and other minerals.