Final answer:
In a ball-and-stick model, a single bond is represented by a single line connecting two balls that represent atoms.
Step-by-step explanation:
To build a single bond in a ball-and-stick model, you only need to use one line. This type of model is a 3-dimensional molecular representation where "balls" embody the atoms, and "sticks," which are straight lines, indicate the bonds connecting these atoms. When constructing a ball-and-stick model to display a single bond, one stick is used between two balls to signify that one pair of electrons is being shared between the two atoms.When building a single bond in a ball-and-stick model, you need to use one line. In a ball-and-stick model, atoms are represented by balls and the bonds between them are represented by sticks. The sticks are drawn as straight lines connecting the centres of the atoms.