Final answer:
The lithosphere is the relatively cool layer of Earth that behaves like a rigid solid, comprised of materials with particles fixed in place due to strong intermolecular forces.
Step-by-step explanation:
The lithosphere is relatively cool and behaves like a rigid solid. In general, when discussing solids, the individual particles of a substance are in fixed positions due to insufficient thermal energy to overcome the intermolecular interactions between them.
Thus, solids have a definite shape and volume, and are almost incompressible. This rigidity is due to the strong intermolecular forces that lock particles in position, making solids (like the lithosphere) act as a rigid body. When solids are cooled from a liquid, they may form crystalline solids with a regular repeating pattern, or amorphous solids such as glasses with particles randomly arranged.
The nature of solids gives them a firm structure, not easily deformed by external pressures or forces.