What layer of the Earth is found between the crust and the core?

The layer of the Earth found between the crust and the core is the mantle. The mantle is a thick layer that makes up a significant portion of the Earth's interior, lying beneath the thin crust and extending down to the outer core. It plays a crucial role in geological processes, including plate tectonics and volcanic activity, due to its semi-solid state that allows for slow movement and convection currents.

This movement helps drive the plates of the Earth's crust, leading to various tectonic activities. Understanding the mantle is essential for comprehending the Earth's structure and the dynamics that shape its surface. The other options, while related to Earth’s systems, do not fit the description of a layer situated between the crust and the core. The atmosphere pertains to the gas layer surrounding the Earth, the lithosphere combines the crust and the uppermost mantle, and the hydrosphere encompasses all water bodies on Earth.