which layer of earth acts as a very effective "insulator," because it's made of rock? Mantle crust outer core inner core

Correct answer: Mantle

Earth is composed of three layer called as crust, mantle, core. Crust is the outer layer of the earth and mantle is the middle layer and core is known as the inner layer of the earth surface.

Mantle is a layer which found in between the crust and core, it is made up of silicate rocky shell with a thickness of 2886 kilometers. It covers the 84% of the earth's volume.

The mantle layer of earth encompasses core layer of the earth which is made up of iron and nickel which covers 15% of the earth's volume. Mantle layer of the earth trap the heat which is being generated inside the core layer of the earth and act as a insulator.

Earlier in the passage this question was provided for, you should be able to find the fallowing text: "The mantle, being made of rock, acts as a very effective insulator."

Answer: Mantle