Which layer of the Earth has the highest elevation?

The continental crust has the highest elevation among the layers of the Earth. This is primarily because the continental crust is composed of lighter, less dense rock compared to the oceanic crust, which is generally denser and lies below sea level. The continental crust can also rise above sea level, forming mountain ranges and plateaus that contribute to its overall higher elevation.

In contrast, the oceanic crust is predominantly found under the oceans and is, therefore, at or below sea level, resulting in a lower average elevation than the continental crust. The upper mantle, while part of the Earth's structure, is not solid but rather behaves like a viscous fluid over geological timescales, and it is also beneath the surface. The inner core, being a solid ball of iron and nickel, is deep within the Earth and does not contribute to surface elevation at all. Hence, the continental crust is indeed recognized for its towering landforms, making it the layer with the highest elevation.