Which of the following defines an object’s resistance to changes in motion?

Inertia is the correct term that defines an object's resistance to changes in motion. It is a fundamental property of matter that means an object will remain at rest or continue moving at a constant velocity unless acted upon by an external force. The greater the mass of an object, the greater its inertia, which means it will be more resistant to any changes in its state of motion.

Understanding inertia is essential in the study of physics and motion, as it explains why a heavy object is harder to start moving or stop than a lighter one. In contrast, velocity refers to the speed of an object in a specific direction, acceleration indicates the rate of change of velocity over time, and momentum is the product of an object's mass and its velocity. While these concepts are related to an object's motion, they do not specifically define the resistance to that motion like inertia does.