A scientist who wants to study the affects of fertilizer on plants sets up an experiment. Plant A gets no fertilizer, Plant B gets 5 mg. of fertilizer each day, and Plant C gets 10mg. of fertilizer each day. Which plant is the control group.

A) Plant C

B) All of them

C) Plant A

D) Plant B

Option C, Plant A

Explanation:

Control group within an experiment is the substance/organism or subject which shall enact as a base for comparison of impact of experiment created on the dependent variables.

Here, the impact of fertilizer is to be studied on plant. Thus, plant set up is dependent variable and amount of fertilizer is an independent variable. Out of all plants one plants is getting 0 amount of fertilizer hence this plant can be used for comparison with other plants which receives the fertilizers.