Which of the following statements defines a controlled experiment?

A controlled experiment is characterized by the involvement of only one independent variable. This approach is crucial because it allows researchers to isolate the effects of that specific variable on the dependent variable. By controlling for other variables, the experiment can provide clear cause-and-effect relationships, making the results more reliable and interpretable.

In a controlled experiment, the researcher manipulates one independent variable while keeping all other potential influences constant. This level of control helps ensure that any observed changes in the dependent variable are directly attributable to the manipulation of the independent variable alone. This methodology enhances the validity of the findings, allowing for precise conclusions about the relationship between the variables studied.