GWD5－Q35（没有搜到满意答案）

liu977

GWD 5-37

Even more than mountainside slides of mud or snow, naturally occurring forest fires promote the survival of aspen trees. Aspens’ need for fire may seem illogical since aspens are particularly vulnerable to fires; whereas the bark of most trees consists of dead cells, the aspen’s bark is a living, functioning tissue that—along with the rest of the tree—succumbs quickly to fire.

The explanation is that each aspen, while appearing to exist separately as a single tree, is in fact only the stem or shoot of a far larger organism.  A group of thousands of aspens can actually constitute a single organism, called a clone, that shares an interconnected root system and a unique set of genes.  Thus, when one aspen—a single stem—dies, the entire clone is affected.  While alive, a stem sends hormones into the root

system to suppress formation of further stems.  But when the stem dies, its hormone signal also ceases.  If a clone loses many stems simultaneously, the resulting hormonal imbalance triggers a huge increase in new, rapidly growing shoots that can outnumber the ones destroyed.  An aspen grove needs to experience fire or some other disturbance regularly, or it will fail to regenerate and spread.  Instead, coniferous trees will invade the aspen grove’s borders and increasingly block out sunlight needed by the aspens.

The primary purpose of the passage is to explain the           

1. qualities that make a particular organism unique
   
2. evolutionary change undergone by a particular organism
   
3. reasons that a phenomenon benefits a particular organism
   
4. way in which two particular organisms compete for a resource
   
5. means by which a particular organism has been able to survive in a barren region

ANS: C   

MINE：E

这题好像没有什么争议，可是C偶怎么也想不通呀，reasons that a phenomenon benefits 这半句还好，长得比较像正确答案，可是当看到organism 这个词时，偶就彻底放弃这个选项了，organism 指的应该是clone，但通篇都是围绕aspen进行的，因此感觉C歪曲了作者的意图

请指教

rakesun

each aspen, while appearing to exist separately as a single tree, is in fact only the stem or shoot of a far larger organism.

aspen就是organism一部分。

liu977

这题感觉还是不大好，虽然看看也只能选这个了。。。怎么能换文章的主角呢？即便它们属于一体，但毕竟不能等同，就好比描述一个人眼睛多么多么漂亮，最后结论是这个人很漂亮，牵强呀。。。

不知道真正考试的题目会不会也是这样得靠比较排除选出答案，那可太费时间啦

rakesun

另外E中barren region说的可不对啊.这地方挺好的,可不是贫瘠的土地啊。呵呵

10gmat

C虽然说的是Organism，但是整篇文章中说fire的最终目的是使得整个organism受益，从而也就是使得aspen tree受益，其实不用在这上面的细节里纠结，可能会更浪费时间。

七重纱

Even more than mountainside slides of mud or snow, naturally occurring forest fires promote the survival of aspen trees.    
第一句就说的山火这个自然现象促进了生物体白杨的生存，也就是对它起积极作用。
随后全都是对上述现象的解释，所以c很准确的反映了文章主旨啦