If you wanted to test whether or not a particular pain reliever was effective in the general population, you would need to design an experiment with an experimental group and a control group. what should be the only difference between these two groups?

The explanation of any natural phenomena requires the proper observation, experiment and research methodology. The experimental design should not violate the ethics and do not cause harm to the living organisms.

The testing of any drug requires the involvement of the experimental group and control group. The experimental group must given the tested drug to known its effect and compared with the control group that will get the placebo understand the psychological effect of the drug.

organ system-an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.