TOEFL Listening: TPO-TOEFL听力TPO - 90OO329MB4O9_I_KR$

How does the professor organize the information in the lecture? A. By describing a phenomenon and the physical structures that make it possible B. By describing several of the dolphin's senses and their relative usefulness C. By contrasting how the dolphin makes two different types of sounds D. By describing an old theory and then a new theory