The lithosphere is the outer solid layer of the Earth, consisting of the crust and the rigid uppermost part of the mantle. It is divided into several tectonic plates that float on the semi-fluid asthenosphere below. The lithosphere plays a crucial role in the formation of geological features such as mountains, volcanoes, and earthquakes. Research in this area involves studying the composition, structure, and dynamics of the lithosphere to better understand Earth's processes and history. This includes investigating plate tectonics, seismic activity, and the interactions between the lithosphere and other Earth systems.