What is described as the tendency of an object to resist a change in motion?

The correct answer is the concept of inertia, which refers to an object's resistance to any change in its state of motion. Inertia is a fundamental property of matter; it means that an object at rest will stay at rest, and an object in motion will continue moving at a constant velocity, unless acted upon by an external force. This concept is rooted in Newton's first law of motion, often referred to as the law of inertia.

Friction is a force that opposes the relative motion between surfaces in contact; it does not describe the inherent property of an object to maintain its motion. Momentum is a measure of the motion of an object, calculated as the product of its mass and velocity, but it does not define the object's resistance to change. Gravity is the force that pulls objects toward each other, such as the attraction between the Earth and an object, but does not relate directly to the concept of maintaining motion. Therefore, inertia is the most accurate term to describe the tendency of an object to resist changes in its motion.