What is lithusphere?

Answer 1

Lithusphere is the segment of earth science which deals with the earth surface and its vanous characteristics.

Simply lithusphere deals with soil system.

Answer 2

The lithosphere is the outermost solid shell of the Earth, made up of the Earth's crust and the upper part of the mantle. It is divided into several tectonic plates that float on the semi-fluid asthenosphere below. The lithosphere is where most geological activity, such as earthquakes and volcanic eruptions, occur.