Question

why do most bar graphs have gaps between the bars?
to confuse the viewer.
to show discrete data categories.
to indicate continuous data.

Explanation:

Bar graphs are used for discrete data (distinct, separate categories). Gaps between bars visually emphasize that each bar represents a separate, non - continuous category. Continuous data (like in histograms) has no gaps as it represents a range of values. Confusing the viewer is not a valid or intended reason.

Answer:

To show discrete data categories.