Which statement best describes friction?

Friction is the force that resists the relative motion of two surfaces in contact. It occurs due to the microscopic irregularities present on the surfaces, as well as the intermolecular forces between them. This resistance to motion is a fundamental characteristic of friction, making it a vital consideration in many engineering applications, such as in the design of brakes or tires.

The implications of friction are significant in various mechanical contexts, as it can enable motion—like enabling a car to grip the road—but can also lead to mechanical wear and energy loss. This concept highlights that while friction can be advantageous in some scenarios, it fundamentally acts to oppose motion, making the selected statement accurate in its description of friction's primary nature.