Correct Response: A. In this experiment, the change in acidity (the variable that will be manipulated) is the independent variable. In line graphs, the independent variable values are on the x-axis. Catalase concentration (B) and percent hydrogen peroxide (D) are constants in this experiment; they do not change. As such, they do not get plotted along either axis on a line graph. The disk rise times (C) are the dependent variable. Changes in the rise time depend on changes in the independent variable, such as acidity in this experiment. In a line graph, the dependent variable is plotted on the y-axis.
