TOEFL Listening: ETS-TOEFL听力机经 - 344BBTZ16SH8X73NP$

Why does the professor mention a small, bony structure in fish that coordinates breathing and eating underwater? A. To emphasize the similarities between fish and land-dwelling animals B. To imply that elpistostegids spend more time on land than underwater C. To explain that elpistostegids had an exceptional ability to breathe underwater D. To explain that some organs evolved faster than others