Final answer:
In vector graphics, curved lines have directional handles known as Bézier handles, which are used to control the line's curvature for creating precise and scalable digital art and designs.
Step-by-step explanation:
The form of vector graphic's lines that has directional handles is not straight lines; it's curved lines, specifically those adjusted using a tool like the pen tool in various graphic design software. These handles, often referred to as Bézier handles, allow for the manipulation of the line's curvature. When drawing with the pen tool, clicking and dragging out from a point creates a pair of these handles, which can then be adjusted to change the line's path between points. Vectors are essential for creating scalable and precise graphics in digital art and design