Answer:
The answer is the second option: Dependent variable, experimental group and control group
Explanation:
Let's list out all possible variables/groups in the option
Independent variable: This is a variable that is intentionally (directly or indirectly) altered by the one doing the experiment but is not affected by any variable/group during the course of the experiment. <u>No Independent variable was mentioned.</u>
Dependent variable: This is a variable that is affected by another variable and is usually the variable been tested during the course of an experiment. <u>The dependent variable here is the effectiveness of a new nutrient supplement.</u>
Experimental group: This is the group that is being treated during the course of an experiment. <u>The experimental group here is the group of identical mice given the supplement.</u>
Control group: This is a reference group that is not given any treatment during the course of an experiment. <u>The control group here is the group of identical mice not given anything.</u>
<u> </u>From the above description, it can be deduced that the parts of the experiment described in the scenario in the question is dependent variable, experimental group and control group.