Answer:
experimental; control groups
Explanation:
The group receiving an experimental treatment is an experimental group. The group is subject to modifications in the testing of the independent variable.
The independent variable attributes are registered as well as the outcome of the dependent variable.
A control group is a distinct group from the experiment so that the testing of the independent variable can not affect the outcomes. This separates the impacts on the experiment of the independent variable and can help rule out possible explanations of the outcomes of the study.