Trisha wants to find out whether a certain pesticide is carcinogenic to amphibians. Trisha is designing an experiment to test the problem. She is planning on exposing frogs of the same species to different amounts of the pesticide. Should Trisha include a control group in her experiment?
A.
Yes, Trisha should have a group of frogs in her experiment that are not exposed to any pesticide at all.
B.
Yes, Trisha should use a different species of frogs as her control group.
C.
No, a control group is not necessary because Trisha will be testing different exposure rates of the pesticide.
D.
No, Trisha will not need a control group because if any frogs develop cancer, it will be obvious that the pesticide is the cause.