OG-26-OG12第三章的！

ruiqijjkkl

Guillemots are birds of Arctic Regions. They feed on fish that gather beneath thin sheets of floating ice, and they nest on nearby land. Guillemots need 80 consecutive snow-free days in a year to raise their chicks, so until average temperatures in the Arctic began to rice recently, the guillemots' range was limited to the southernmost Arctic coast. Therefore, if the warming continues, the guillemots' range will probably be enlarged by being extended northward along the coast.

Which of the following, if true, most seriously weakens the argument?
A. Even when the warming trend continues, there will still be years in which guillemot chicks are killed by an unusually early snow.
B. If the Arctic warming continues, guillemots' current predators are likely to succeed in extending their own range farther north.
C. Guillemots nest in coastal areas, where temperatures are generally high than inland areas.
D. If the Arctic warming continues, much of the thin ice in the southern Arctic will disappear.
E. The fist that guillemots eat are currently preyed on by a wilder variety of predators in the southernmost Arctic regions than they are farther north.
我始终不明白，D很明显是要选的，但是B呢，似乎有其道理？欢迎大家讨论哦O(∩_∩)O

ruiqijjkkl

顶上去哟~

winny莹

我觉得吧，无论是文章还是题目都没有说明这个鸟的天敌到底住在南边还是北边，这样岂不是就留下了一个逻辑漏洞？
如果说这鸟天敌他住南边，随气候变暖就向北扩张栖息地，好像就会和这文章的鸟一样，一起向北扩张了栖息地，可能就会给这鸟带来威胁。
但是另一方面，如果这鸟的天敌本来就住北边，那可能就不会影响到南边的鸟了吧。

反正我觉得B选项还是存在逻辑漏洞的，没有D这么完美。GMAT考试毕竟不是一个严格的统一划分的考试，很灵活的，题目都要求选最怎样的，其他没选上的不代表就是错的，可能只是没那么完美吧……

ruiqijjkkl

谢谢大帅~~
这是个新鲜的解释~有一定道理呵！

ruiqijjkkl

顶一下~还有没有大虾有其他看法呢？

magicinair

我觉得D选项对应的是Guillemots应该迁徙到北面去而不是文中的扩大到北面去，所以有削弱。B选项说明predator本来就在南面（否则怎么扩张到北方？）本来就存在了，所以对Guillemots的扩张到北方是没有影响的，因为本来就会遭遇到predator

ruiqijjkkl

你很细心额！
确实predator应该原先在南部的。这样就把楼上的MM观点给推翻了~

恒河猴

predator应该与prey生活在同一栖居地，随着变暖，predator会向北迁移，原栖居地缺少了predator就会更宜居，为了避开predator，G鸟就不会向北迁移，相当于驳斥了文章的前提：g extend northward along the coast，进而削弱了文章。但答案是说，g's situation has not changed, so this is not an argument against their enlarged range。显然是against了啊。。。不迁移领地肯定不会变大啊，实在是不明白。。。
我做的时候是选的B，看了答案后才觉得，哦，原来D也有道理，但是没能说服我B不对。

恒河猴

恒河猴 发表于 2016-7-5 22:11
predator应该与prey生活在同一栖居地，随着变暖，predator会向北迁移，原栖居地缺少了predator就会更宜居， ...

manhattan 上看来的。

You might have gotten it down to B & D like I did. D trumps B because B is not negating the fact that G's range will not extend Northward. B is saying, G's predators will also go northward. So it might be that both G and its predators move north and few G survive. If that is the case, G did extend northward.

Whereas in D, the ice sheets will melt, G cannot stand on water as they did on ice sheets to pick the fish. If they try to do so, they risk and probably sink in water and die. If they dont do so, it is difficult to get food in the arctic and hence risk extinction. Forget expansion.

我明白了，就是说predator北迁不代表G不会北迁，G北迁的话不能说明领地不会增大，所以不能削弱文章。