Which of the following is not true concerning the layers of the earth?
a. the core is mostly composed of metals.
b. the mantle has both solid and liquid regions.
c. the layers of earth are uniform in thickness.
d. the lithosphere includes both the crust and upper, solid mantle

c. The layers of Earth are uniform in thickness.

Explanation:

The Earth is basically made up of three layers:

- Earth's Crust: Solid superficial layer that surrounds the Earth. (30 to 40 km thick)

- Mantle: layer just below the crust. It is formed by several types of rocks that, due to the high temperatures, are in the pasty state and are called magma.(to a depth of 2900 km)

- Core: Comprises the central part of the planet and is believed to be formed by metals such as iron and nickel at very high temperatures. (from 2900 to 6371 km deep)