Why would it be difficult to include water vapor on a pie chart?

It would be difficult to include water vapor on a pie chart because water vapor is a gas and not a tangible substance that can be visually represented in a chart format. Pie charts are typically used to show proportions of discrete categories or values, and water vapor is a continuous variable that does not fit into this framework. Additionally, water vapor is often present in varying and dynamic amounts in the atmosphere, making it challenging to accurately quantify and represent on a static chart.