Which best describes the purpose of a control sample?

A control sample serves as a sample used to eliminate errors or minimize them. Also, it is used to prevent the effect of one parameter which is not the subject being studied. For instance, in an adsorption experiment a control sample is always included wherein in a flask it only contains the adsorbate solution. The said sample is responsible for calculating how much of the adsorbate is being adsorbed on the sides of the flask.