TOEFL Listening: ETS-TOEFL听力机经 - 54IHJCW59VR6L5AFP$

What does the professor mainly discuss? A. A theory about the breakup of the Gondwanan supercontinent during the Cambrian period. B. A possible relationship between plate tectonics and the relatively sudden appearance of complex life on Earth. C. How a massive mountain range might have affected climate during the Cambrian period. D. A new tool developed by Australian researchers to analyze fossils found in ancient seabeds.