TOEFL Listening: ETS-TOEFL听力机经 - M1359391XM7UL1D1P$

What does the professor imply about manatees' tactile hairs? A. They might serve the same function as a lateral line. B. They probably evolve to help manatees hear better. C. They are useful only during a limited period of a manatee's life. D. They are located only on the manatees' faces.