What term describes an object's tendency to remain at rest or in motion at a constant velocity?

The correct term that describes an object's tendency to remain at rest or in motion at a constant velocity is inertia. Inertia is a fundamental property of matter that reflects its resistance to changes in its state of motion. According to Newton's first law of motion, an object will continue in its state of rest or uniform motion unless acted upon by a net external force. This means that objects tend to "keep doing what they’re doing," which defines inertia.

Momentum, while related to motion, specifically refers to the quantity of motion an object has, which is dependent on both its mass and velocity. Force is an external influence that can change an object's motion rather than something inherent within the object itself. Resistance generally refers to the opposition to motion, such as friction, but does not encompass the broader idea of maintaining a state of motion or rest. Thus, inertia is the best term to describe the tendency of an object to maintain its current state.