That all depends on what kind of quantity you are graphing. It might be speed, temperature, altitude, relative humidity, barometric pressure, etc. Each would use a different unit.
The Y-axis I think. I'm not sure if that's what you meant though XP
The correct SI unit for the vertical axis in a graph depends on the type of measurement being represented. Common examples include meters for distance, kilograms for mass, and Kelvin for temperature. Identifying what is being measured will guide you to the appropriate unit.
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