TOEFL Listening: TPO-TOEFL阅读TPO - KKD5XL5829Q6BC03N$

According to paragraph 4, which of the following statements explains the importance of the discovery of high levels of iridium rocks? A. It provided evidence that overexposure to solar radiation led to the K-T extinction. B. It showed that more than one cataclysmic event was responsible for the K-T extinction. C. It suggested that the cause of the K-T extinction may have been a meteorite striking Earth. D. It provided evidence that the K-T extinction occurred 65 million years ago.