Final answer:
In a graph, the independent variable is manipulated to observe its effect on the dependent variable, which is measured by the experimenter.
Step-by-step explanation:
In a graph, the independent variable differs from the dependent variable in how they are used in an experiment. The independent variable is the one that is manipulated or controlled by the experimenter to observe the effect it has on the dependent variable. In contrast, the dependent variable is the one that is expected to change as a result of the manipulation of the independent variable. It is what the researcher measures. For example, if a scientist is studying the effect of sunlight on plant growth, the amount of sunlight (the independent variable) would be varied to observe the change in plant growth (the dependent variable).
Thus, the correct answer to how the independent variable in a graph differs from the dependent variable is: a) The independent variable is manipulated, while the dependent variable responds to changes.