What is the primary difference between a ray and a line segment?

A ray is defined by its starting point and continues infinitely in one direction. This unique characteristic distinguishes it from a line segment, which has two endpoints and does not extend beyond those points. The concept of a ray emphasizes its directional nature, beginning from a specific point while extending endlessly away from that point. This understanding is essential for grasping geometric concepts involving angles and other constructs where one-directional lines are significant.

The other statements do not accurately represent the nature of a ray or a line segment. For instance, a line segment clearly does not have the infinite properties that characterize a ray, and its construct involves definite endpoints.