Question

What is the "basics" of a proper experiment?

There are two randomly selected groups. One group is given a control the other one is called the treatment.
There are two groups. One group is given a treatment the other one is called the control.
There are selected groups. One group is given a control the other one is called the treatment.
There are two randomly selected groups. One group is given a treatment the other one is called the control.

Answer 1

sorry in my sense, an experiment once only changes one variable and need a control setup for experimental setup to make sure is fair test