Final answer:
A control group is a standard reference experiment done under identical conditions by omitting the independent variable whose effect is being tested. It helps establish a baseline comparison and determine whether observed effects are truly caused by the variable being tested.
Step-by-step explanation:
A standard reference experiment done under parallel or identical conditions by omitting the independent variable whose effect is being tested is called a control group. In this experiment, one group is exposed to the independent variable or experimental manipulation, while the other group, the control group, is not. The purpose of the control group is to establish a baseline comparison and to ensure that any changes in the dependent variable can be attributed to the independent variable. It helps researchers determine whether the observed effects are truly caused by the variable being tested or by other factors.