TOEFL Listening: ETS-TOEFL听力机经 - 451ADC9IF91F9D59P$

In the study that the professor discusses, what grooming behavior was shown by the smallest of the three alpha male chimpanzees? A. He never groomed other chimpanzees in the group. B. He did not allow himself to be groomed by other chimpanzees. C. He only groomed larger male chimpanzees. D. He spent a lot of time grooming other chimpanzees.