题目选项分析

Perkins: According to an article I read, the woolly mammoth`s extinction in North America coincided with a migration of humans onto the continent 12,000 years ago, and stone spearheads from this period indicate that these people were hunters. But the author's contention that being hunted by humans contributed to the woolly mammoth`s extinction is surely wrong since, as paleontologists know, no spearheads have ever been found among the many mammoth bones that have been unearthed.

Which of the following, if true, provides the strongest reason for discounting the evidence Perkins cites in arguing against the contention that being hunted by humans contributed to the North American extinction of woolly mammoths?

【选项】At sites where mammoth bones dating from 12,000 years ago have been unearthed, bones of other mammals have rarely been found.