TOEFL Listening: ETS-TOEFL听力机经 - N82WEE4YAO8K9B18P$

What point does the professor emphasize when she mention that certain elpistostegids lacked a gill cover? A. Their necks were vulnerable to attack while they were underwater B. They could breathe in large amount of air C. They developed lungs more quickly than was previously thought D. While they were on land, their necks were flexible