TOEFL Listening: ETS-TOEFL听力机经 - S9K111CBSIOI122PP$

Why does the professor point out that the glacial pool has not frozen even though its temperature is below the freezing point? A. To point out that sulfate could not be recycled in water that has frozen. B. To emphasize that the pool is very salty. C. To point out that seawater is colder today than it was two million years ago. D. To imply that the amount of water in the pool has been slowly decreasing.