free of tooth breakage << 一題OG閱讀問題

zhouxiaoning

想請問板上的高手牛人一題OG閱讀問題

不知道有沒有人也有寫到.....

[文章如下]
A recent study has provided clues to predator-prey dynamics in the late Pleistocene era. Researchers compared the number of tooth fractures in present-day carnivores with tooth fractures in carnivores that lived 36,000 to 10,000 years ago and that were preserved in the Rancho La Brea tar pits in Los Angeles. The breakage frequencies in the extinct species were strikingly higher than those in the present-day species.

In considering possible explanations for this finding, the researchers dismissed demographic bias because older individuals were not overrepresented in the fossil samples. They rejected preservational bias because a total absence of breakage in two extinct species demonstrated that the fractures were not the result of abrasion within the pits. They ruled out local bias because breakage data obtained from other Pleistocene sites were similar to the La Brea data. The explanation they consider most plausible is behavioral differences between extinct and present-day carnivores-in particular, more contact between the teeth of predators and the bones of prey due to more thorough consumption of carcasses by the extinct species. Such thorough carcass consumption implies to the researchers either that prey availability was low, at least seasonally, or that there was intense competition over kills and a high rate of carcass theft due to relatively high predator densities.

[題目如下]
The passage suggests that if the researchers had not found that two extinct carnivore species were free of tooth breakage, the researchers would have concluded that
    

(A)   The difference in breakage frequencies could have been the result of damage to the fossile remains in the La Brea pits
(B)    The fossils in other Pleistocene sites could have higher breakage frequencies than do the fossils in the La Brea pits
(C)    Pleistocene carnivore species probably behaved very similarly to one another with respect to consumption of carcass
(D)    All Pleistocene carnivores species differed behaviorally from present-day carnivore species.
(E)     Predator desities during the Pleistocene era were extremely high

我整個人卡在文中的"total absence of breakage in two extinct species demonstrated that the fractures were not the result of abrasion within the pits"

囧rz......  希望板上牛人強者可以分享殺這題的看法. 無盡感謝!!

(A)   The difference in breakage frequencies could have been the result of damage to the fossile remains in the La Brea pits
(B)    The fossils in other Pleistocene sites could have higher breakage frequencies than do the fossils in the La Brea pits
(C)    Pleistocene carnivore species probably behaved very similarly to one another with respect to consumption of carcass
(D)    All Pleistocene carnivores species differed behaviorally from present-day carnivore species.
(E)     Predator desities during the Pleistocene era were extremely high

我整個人卡在文中的"total absence of breakage in two extinct species demonstrated that the fractures were not the result of abrasion within the pits"

囧rz......  希望板上牛人強者可以分享殺這題的看法. 無盡感謝!!

[此贴子已经被作者于2009-1-19 3:18:44编辑过]

烤G族

This question asks you to identify a conclusion that the researchers might have reached if the y had not found the two extinct carnivore species that were free of tooth breakage. The best answer is A. The researchers used the evidence of extinct carnivore species that were free of tooth breakage to eliminate preservational bias, that is, to eliminate the possibility that fractures were caused by abrasion in the pits. If every extinct species found had shown tooth breakage, the possibility that factures were caused by abrasion within the pits could not have been eliminated, and the researcher would have concluded that the damage could have occurred in the La Brea pits. Choice B is incorrect because there is nothing in the passage to suggest the relevance of these two species to predicting breakage frequency at other sites. Choice C can be eliminated because the passage suggests that if every extinct species found in the La Brea pits showed tooth breakage, researcher would have considered that preservational bias, not similarity of consumption behavior in Pleistocene carnivores species, was responsible for the finding. Choice D can be eliminated because the passage suggests that if every extinct species found in the La Brea pits showed tooth breakage, researchers would have concluded that the fractures could have been caused by preservational bias rather than by behavior in Pleistocene carnivore species that differed from behavior in present day species. Choice E is incorrect: if every extinct species found in the La Brea pits showed tooth breakage, the breakage could have been attributable to preservational bias rather than to high predator densities during the Pleistocene era.