TOEFL Reading: ETS-TOEFL阅读机经 - I7U3XWY7R7T0YMEZL$

According to paragraph 5, which of the following was true of the first tetrapods? A. They became dependent for food on organisms already living on land. B. They needed to develop new mechanisms for obtaining nutrients. C. They continued to live in close association with aquatic environments. D. They were evolutionarily far removed from their rhipidistian ancestors.