In the scenario described, Lexi folded her paper in such a way that point C was on top of point D, creating a crease where the line segment intersects the fold. This crease, which is represented by point E, is the segment bisector of CD̅̅̅̅̅̅̅.
Therefore, the line that serves as the segment bisector in this scenario is:
CD̅̅̅̅̅̅̅
This is because the fold at point E divides the line segment CD into two equal parts.