Question

why must an experiment have a control group? a control group acts as a baseline for comparison when changing the dependent variable. a control group ensures that only the independent variable is affecting the results of the experiment. a control group acts as a baseline for comparison when changing the independent variable. a control group ensures that only the dependent variable is affecting the results of the experiment.

Explanation:

The control group in an experiment is not exposed to the independent - variable manipulation. It serves as a baseline for comparison when the independent variable is changed in the experimental group. This helps in determining if the changes in the dependent variable are due to the independent variable or other factors.

Answer:

C. A control group acts as a baseline for comparison when changing the independent variable.