What is required for each axis on a graph?

• A. Labels
• B. Color
• C. Gridlines
• D. Scale

Answer: (A)

The key idea here is that axis labels identify what each axis represents and the units used. A graph only makes sense if you know what you're measuring on each axis, so labeling tells you whether the horizontal axis is time, distance, velocity, etc., and what units to read off (for example, Time in seconds and Distance in meters). Without labels, the values on the axes are ambiguous, and you can’t reliably interpret the relationship shown. Gridlines or color can help readability, and a proper scale is important for reading exact numbers, but the essential requirement for each axis is a clear label with its units.