Lithosphere
Lithosphere is known to be outermost layer of the Earth of about 100km thick and it is a rigid layer that includes the brittle upper portion of the mantle and the crust. Lithosphere is the hard outer region which includes all of the crust and the uppermost mantle. Furthermore, lithosphere is also the coolest layer of the earth in term of temperature, with the heat from the lower layers generating the plate movement.
