GEOLOGY

Detailed explanation-1: -The core is made of two layers: the outer core, which borders the mantle, and the inner core. The boundary separating these regions is called the Bullen discontinuity. Outer Core The outer core, about 2, 200 kilometers (1, 367 miles) thick, is mostly composed of liquid iron and nickel.

Detailed explanation-2: -Scientists believe that the inner core is the hottest layer of the Earth, that it is composed mostly of iron and nickel, and that although it is hot enough to be a liquid, it acts as a solid because of the immense amount of pressure on it.

Detailed explanation-3: -The inner core is at the center of the Earth because it is the densest, made of solid iron and nickel.