What must be present on every axis according to the rules?

• A. Labels
• B. A color
• C. Gridlines
• D. Titles

Answer: (A)

Axis labels are essential because they tell you what each axis represents and what units are being used. With clear labels, you instantly know what is being measured on the horizontal and vertical directions, and you can read and compare values correctly. Without labels, the numbers on the axes could be meaningless or misinterpreted, making the graph hard to understand. The other features—color, gridlines, and a title—are helpful but not required on every axis. Color is just a visual cue, gridlines aid reading values but don’t identify what the axis measures, and a title describes the overall graph rather than naming each axis. So labeling the axes is the necessary rule.