TOEFL Listening: ETS-TOEFL听力机经 - E91M43751M3MZ7Y9P$

What point does the professor make about the bacteria present in yogurt? A. The bacteria can cause sickness in some people. B. The bacteria in some yogurt brands are difficult to digest. C. Live bacteria are not present in all yogurt brands. D. The bacteria act like an antibiotic in the digestive system.