What visualization method uses vertical and horizontal axes to show several variables simultaneously?

The correct answer is a polygon. A polygon, particularly in the context of data visualization, typically refers to a line graph that can display multiple data series or variables at once. By using vertical and horizontal axes, it allows viewers to see trends and relationships among different variables. Each variable can be represented by its own line, which intersects the axes at points corresponding to the variable's value, enabling easy comparison and analysis.

This visualization method is particularly useful when you need to compare several series of data over a common interval or range, as it effectively highlights the relationships and changes among multiple sets of data in a single view. It is a tool often used in statistical and data analysis to provide a clear illustration of multiple dimensions within the data, making it a versatile choice for complex datasets.