How do you identify the control in a controlled experiment?

Question

How do you identify the control in a controlled experiment?

Answer 1

it is very important that you also mention in what context you asking this question take an example of drug research then control is one with only non-medical ingredients and test sample is one with medical+non-medical ingredients. Basically control is something standard or constant whose experimetal data or behaviour has already been established you can use control as a reference satndard or you can use control to remove variation due other factors which have not been included in the study