Which of the following layers of earth is a liquid layer with the highest density?

A. Athensphere
B. Lithosphere
C. Outer core
D. Mesosphere

C. Outer core

The layer of the Earth that is a liquid layer with the highest density is the C. Outer core.

To determine which layer of the Earth is a liquid layer with the highest density, we need to understand the composition and characteristics of each layer mentioned.

A. Athenosphere: The asthenosphere is a semi-fluid layer located below the lithosphere. It is made up of partially molten rock that allows tectonic plates to move on top of it.

B. Lithosphere: The lithosphere is the rigid outermost layer of the Earth and is composed of the crust and a portion of the upper mantle. It is solid and broken into tectonic plates.

C. Outer Core: The outer core is a liquid layer located between the Earth's inner core and mantle. It is mostly composed of molten iron and nickel.

D. Mesosphere: The mesosphere is a solid and rigid layer situated between the Earth's lower mantle and the outer core. It is made up of solid rock.

Given this information, it is evident that the liquid layer with the highest density among the options is the C. Outer Core. The outer core is composed mainly of molten iron and nickel, which are dense metals.

To summarize, the correct answer is C. Outer Core, and we reached this conclusion by understanding the composition and characteristics of each layer of the Earth.