TOEFL Reading: ETS-TOEFL阅读机经 - L13747S7Y1MIBNDBL$

According to paragraph 1, which of the following provides evidence that natural selection does not always lead to evolutionary progress? A. Most evolutionary lines that once existed on Earth have become extinct. B. Evolutionary lines usually weaken as they increase in age. C. The history of evolution shows that many evolutionary lines can become extinct at the same time. D. So far, less than one percent of evolutionary lines have achieved such perfect adaptation to their environment that they will never become extinct.