What is a control setup?
Hereof, what is the control set up in an experiment?
When an experiment is carried out, it's important that only one variable is tested so that any changes observed can't be attributed to another factor. A control set-up "controls" for other factors. Ideally it's the exact same set-up as the experiment except for one difference - the variable being tested.
Similarly, you may ask, what is the purpose of a control setup?
A control set-up is often needed to ensure that the experiment is valid & accurate. Ultimately, the control set-up is in place to ensure that the measured variable (dependent variable) is affected only by the changed variable (independent variable) and not any other variable in the experiment.
In scientific experiments, a scientific control is one in which the subject or a group would not be tested for the dependent variable(s). A biological control is the use of organism(s) to control the population of another group of organisms.