Local farmers think that a commonly used pesticide is responsible for the increase in appearance of frogs with an additional appendage. To test this hypothesis, frogs are injected with a small amount of pesticide mixed in ethanol. The frogs are allowed to produce offspring to test the effect of the pesticide. Which of the following would be the best controlled experiment? A. One group is injected with ethanol, and one group is injected with pesticide. B. One group is injected with pesticide. C. One group is injected with pesticide, and one group is not injected with anything. D. One group is injected with ethanol, one group is injected with pesticide, and one group is not injected with anything.
