What best encapsulates the concept of motion in physics?

The concept of motion in physics is fundamentally about the change in the position of an object over time. When we say that an object is in motion, we are observing that it has moved from one location to another and this can be quantified using distance, speed, and velocity. Motion isn't just about being in a different place; it's a description of how that change occurs, often involving various factors such as time intervals and trajectories.

This dynamic nature of motion distinguishes it from other concepts in physics. For instance, the idea of stillness in space does not reflect any change, while forces acting upon an object describe factors that can influence its motion rather than the motion itself. Additionally, energy conservation pertains to the principles surrounding energy transfer and transformation, rather than the basic definition of motion. Thus, the correct choice effectively outlines the essence of motion in a clear and precise manner.