Final answer:
A line segment is a part of a line that has two endpoints. A beam of light can be considered as a line segment because its path can be modeled as straight lines.
Step-by-step explanation:
A line segment is a part of a line that has two endpoints. It is a straight path connecting two points. Out of the given options, the edge of a book and the corner of a box cannot be considered as line segments because they are not straight paths.
On the other hand, a beam of light can be considered as a line segment. Although light may change direction, we can model its path as straight lines. Therefore, a beam of light represents a line segment.
However, the floor of a classroom does not represent a line segment. It is a flat surface and does not have two distinct endpoints.