Scientists have investigated the relationship between olfactory receptor (OR) genes (which provide the basis for an animal's sense of smell) and trichromatic vision in primates. (Trichromatic vision is a sophisticated form of full-color vision.) It appears that as color vision evolved in primates, they became less reliant on their sense of smell and lost function in some of their OR genes.

Group control group #1 experimental group yes yes yes control group #2 no new drug orange juice bed rest no yes no yes ves which of the following is the best explanation of why a second control group was included in this experiment? o a. to provide the volunteers in the study with something to drink o b. to prove that the common cold cannot be cured c. to confuse anyone who is trying to steal their new drug and sell it as their own invention o d. to researchers conclude that results are related to the new drug and not to the orange juice submit e previous