According to a theory advanced by researcher Paul Martin, the wave of species extinctions that occurred Line in North America about 11,000 years (5) ago, at the end of the Pleistocene era, can be directly attributed to the arrival of humans, i.e., the Paleoindians, who were ancestors of modern Native Americans. However, anthropologist (10) Shepard Krech points out that large animal species vanished even in areas where there is no evidence to demon- strate that Paleoindians hunted them. Nor were extinctions confined to large (15) animals: small animals, plants, and insects disappeared, presumably not all through human consumption. Krech also contradicts Martin’s exclusion of climatic change as an explanation by (20) asserting that widespread climatic change did indeed occur at the end of the Pleistocene. Still, Krech attributes secondary if not primary responsibility for the extinctions to the Paleoindians, (25) arguing that humans have produced local extinctions elsewhere. But, according to historian Richard White, even the attribution of secondary responsibility may not be supported (30) by the evidence. White observes that Martin’s thesis depends on coinciding dates for the arrival of humans and the decline of large animal species, and Krech, though aware that the dates (35) are controversial, does not challenge them; yet recent archaeological discoveries are providing evidence that the date of human arrival was much earlier than 11,000 years ago.
Q11: Which of the following, if true, would most weaken the author’s argument in lines 18-26 (“Furthermore … sloth bear cubs”)? - Cub-carrying behavior has been observed in many non-myrmecophagous mammals.
- Many of the largest myrmecophagous mammals do not typically exhibit cub-carrying behavior.
- Some sloth bears have home ranges that are smaller in size than the average home ranges of black bears.
- The locomotion of black bears is significantly more efficient than the locomotion of sloth bears.
- The habitat of black bears consists of terrain that is significantly more varied than that of the habitat of sloth bears.
答案是E,我感觉D也可以啊。哪位能解释一下? |