Which of the following is typically the least dense layer of the Earth?

The continental crust is typically the least dense layer of the Earth due to its composition and thickness. It is primarily made up of lighter, granitic rocks compared to the denser materials found in the core and mantle. The core is primarily composed of iron and nikeli, making it very dense, while the mantle is made up of silicate minerals under high pressure and temperature that also contribute to a higher density.

In comparison, the oceanic crust is denser than the continental crust because it is primarily composed of basaltic rocks, which are heavier than the granitic rocks that dominate the continental crust. While the continental crust can vary in thickness, it is generally thicker and less dense than the oceanic crust, resulting in it being buoyant and sitting higher on the mantle. This characteristic contributes to the overall structure of the Earth's surface and the formation of continents.