What is the primary feature of rotational motion?

The primary feature of rotational motion is the movement of an object turning about an axis. In this type of motion, every point in the object moves in a circular path around a central axis, which could be internal, as in the case of a spinning top, or external, as in the case of the Earth rotating around its axis. This is distinctly different from linear motion, where an object moves along a straight line or across a surface without the circular or pivoting nature inherent to rotation.

When considering other potential answers, changing the position of an object refers more broadly to translations that do not specify rotation and can occur in any direction. Movement along a straight line specifically characterizes linear motion, and translating without changing speed involves uniform motion, which again is unrelated to the characteristics of rotation. Hence, the essence of rotational motion lies in its unique feature of turning around an axis, making the correct answer clearly distinguishable in the context of motion types.