Answer:
A control group setup in an experiment is used to see if there are other variables in play during the experiment. Say I was to test which type of blood is a shark's favorite, my control would be putting red paint in one of the set ups to see if the shark is just interested in the red color of blood, instead of the other types of blood.
Explanation:
By binding to DNA it triggers the transcription of a specific gene.
The answer is "Groundwater"