Final answer:
The x-axis of a line chart typically represents the independent variable, such as time in a position vs. time graph.
Step-by-step explanation:
The x-axis of a line chart represents the independent variable, which is the variable that we can control or that occurs inherently without dependencies. For instance, in a graph of position versus time, the time would typically be the independent variable, plotted on the x-axis, while the position would be the dependent variable, plotted on the y-axis. Understanding which variable to plot on each axis is crucial because it helps to correctly interpret the relationship between the variables represented in the graph. The slope of such a graph indicates the rate of change of the dependent variable relative to the independent variable.