og 12 第7题

soiler

7. The researchers’ conclusion concerning the absenc
of demographic bias would be most seriously
undermined if it were found that
(A)  the older an individual carnivore is, the more
likely it is to have a large number of tooth
fractures
(B)  the average age at death of a present-day
carnivore is greater than was the average age
death of a Pleistocene carnivore
(C)  in Pleistocene carnivore species, older
individuals consumed carcasses as thoroughl
as did younger individuals
(D)  the methods used to determine animals’ ages
fossil samples tend to misidentify many older
individuals as younger individuals
(E)  data concerning the ages of fossil samples
cannot provide reliable information about
behavioral differences between extinct
carnivores and present-day carnivores

对应原文为：In considering possible explanations for this
?nding, the researchers dismissed demographic bias
because older individuals were not overrepresented
in the fossil samples.
正确选项为D，这个没有疑问，但是为什么说A选项支持呢？

尾巴儿

我是这么理解的，先看a的意思，说的是肉食动物越老，它们的牙齿将会有更多的fracture。
回到原文看研究人员排除demographic bias的原因：年老的肉食动物的破损牙齿并没有在所有化石样本中overrepresented，这也就暗示了，牙齿破损并非由于年龄造成（假如a成立，即牙齿破损和年龄正相关。但实际情况也就是样本中没有体现这种正相关，也就说明了研究人员的排除demographic bias是正确的，fracture和older没关系。）因此，a是支持研究人员的理论的。