TOEFL Listening: ETS-TOEFL听力机经 - K44K544TGI4846GQP$

What do the ice-dam theory and the meteor-impact theory both assure? A. That all vegetation died during the Younger Dryas. B. That melting ice caused the Younger Dryas. C. That the Younger Drays contributed to modern-day global warming. D. That the element indium played a key role in the Younger Dryas.