TOEFL Listening: ETS-TOEFL听力机经 - M4LK48P13N6J37TDP$

According to the professor, what factors might have created the conditions for a Snowball Earth event? A. A change in the proportion of land and wafer covering Earth's surface B. The cooling effect of the oceans' low surface albedo C. A change in the atmosphere that lowered Earth's surface temperature D. A continuing cycle of radiation reflection and ice growth