What is so special about the outer core? 1 It is made of rock
2 It is the hottest layer
3 It is made of solid metal
4 It is made of liquid metal

It is made of liquid metal.

Explanation:

Earth is divided into few layers, and those layers are further divided into subdivisions. The layer in the central part of the planet is the core, and the core is divided into the inner core and outer core. The outer core is wrapped around the inner core.

The outer core is very thick, 2,200 km thick in fact. Unlike the inner core which is solid, the outer core is made up of liquid metal, mostly liquid iron and nickel. The metal is in liquid form because of the very high temperature and pressure. Because it is composed of metal, the outer core conducts electricity with ease. This layer also is in constant movement, or rather the material in it is constant movement, and this is due to the intense convection.