TOEFL Listening: ETS-TOEFL听力机经 - K144N223YRQ83281P$

The professor discusses research done on ancient coral reefs. How was the research conducted? A. The reefs were studied to determine the kinds of animals that lived there. B. Different layers of ancient coral were analyzed to determine their age. C. The reefs were examined for patterns of wind erosion. D. The composition of ancient reefs was compared to that of living reefs.