OG16逻辑100题

tyzs

mnimi 发表于 2015-12-14 14:51
另外，我觉得你这么解释稍微有点较真儿，因为close related这个词想要说明的就是生理结构相近，原因相近 ...

好吧，灰常感谢！！以前一直以为gmat的逻辑答案都是无懈可击的。。

mnimi

tyzs 发表于 2015-12-14 23:28
好吧，灰常感谢！！以前一直以为gmat的逻辑答案都是无懈可击的。。

Gmat题目灰常灵活~~~与其说考逻辑我倒觉得是考人在压力下如何迅速作出选择。当然了这只是我的想法，还请NN拍砖~

阿福爱吃水果糖

A certain cultivated herb is one of a group of closely related plants that thrive in soil with high concentrations of metals that are toxic to most other plants，意思是那一组相似的植物里只有某一种可以生存，其他不行。而不是这一组的可以生存，其他植物不行。

adsdsd

阿福爱吃水果糖 发表于 2016-1-31 08:33
A certain cultivated herb is one of a group of closely related plants that thrive in soil with high  ...

我不太认同楼上的观点
A certain cultivated herb is one of a group of closely related plants that thrive in soil with high concentrations of metals that are toxic to most other plants   
意思就是这一组中的所有植物都可以在高浓度的M中生存，而其他植物不行。
因为that 修饰最近的名词，就是a group of closely related plants
请指教！
           

这道题我也做错了，OG中B项的解释是：
B   Correct. If the closely related plants do not produce much histidine, whatever other factor allows them to thrive in metal-rich soils would likely account for why the herb thrives in those soils as well.
就是说这一组中其他植物如果没有产生histidine的能力的话，就能够证明存在其他因素使它们可以在高浓度的M中生存

楼主的疑问“同一组的其他植物的特征不能代表那个herb的特征。”我觉得是对的，不过B和其他选项比较的话，只有B最好了
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http://gmatclub.com/forum/a-certain-cultivated-herb-is-one-of-a-group-of-closely-related-plants-205067.html
在上面网站中也有人问过这个问题，贴出来供参考：
各项分析：
(B). Here's why  -

(A) -> Whether it thrives in other soil or not is not relevant to finding out if it thrives in metal rich soil because of histidine. This option is out of scope to what's asked.
(B) -> If true, will give us confidence that histidine is indeed a critical component of surviving the toxic metal rich soil. This would indicate that the mentioned herb has something common with other plants that thrive in the patch. Most likely, if this is the case, the common factor is the one that helps them survive.
(C) -> Irrelevant. Consider two cases - A. some other amino acid is produced in large quantities - it may be a compound not related to toxic survival (it could be something that causes leaves to grow bigger, for example). B. some other amino acid is produced in unusually low quantities - this does not help the case of plant surviving because of histidine. What other acids do, or their quantities is not helpful in finding if histidine is the key factor for survival.
(D) -> This is tricky. Suppose metal concentration is reduced over time. Also suppose that this is due to neutralizing effect of histidine. All this says is that the plant reduces concentration of metal. Doesn't say anything about whether histidine is the critical factor in survival. It could be anything else. The effect histidine has on the metal concentration may not be key to the plant's survival. Any other factor (say a toxic filtering mechanism in the plant's roots) may be the most critical. So, histidine's effect on soil is not the most helpful in finding out if histidine is THE most important feature that helps survival.
(E) -> Age of the plant is not in scope for the argument and is not needed to find if histidine is the true savior.

问题：

sun01 wrote:
I have one doubt.

We have to evaluate that "Hence, the herb's high histidine production must be the key feature that allows it to grow in metal-rich soils."
.

Argument clearly states that "A certain cultivated herb is one of a group of closely related plants that thrive in soil with high concentrations of metals that are toxic to most other plants".

The information in option B provides that others of closely related groups produces the amino acids. How does this information impact the conclusion? if you say no, this clearly states that the other group doesn't have capability to grow in metal rich area. but it will not affect that herb's high histidine production must be the key feature that allows it to grow in metal-rich soils.

回答：
I think you have misunderstood  the argument a bit. Here is what it says:
Argument:
- A certain cultivated herb is one of a group of closely related plants that thrive in soil with high concentrations of metals that are toxic to most other plants.
So this herb is one of a group of plants. All plants in this group of plants thrive in soil with high concentration of metals. These metals are toxic to most other plants.  
- Agronomists studying the growth of this herb have discovered that it produces large amounts of histidine, an amino acid that, in test - tube solutions, renders these metals chemically inert.
We are given that this herb produces histidine which makes these metals inactive.
Conclusion: The herb's high histidine production must be the key feature that allows it to grow in metal-rich soils.

We don't really know what makes the herb flourish in high metal soil. It could be histidine or it could be that it produces 10 other chemicals which allow it to flourish in metal rich soil. Since all these plants are closely related and only they are the ones who thrive in metal rich soils, it is likely that they have some common feature that helps them thrive. We are guessing its histidine. How do we find out whether our claim holds value?
If we evaluate whether the other plants in the group also produce histidine, it helps us. How? If other plants also produce lots of histidine, it becomes more likely that histidine is the one which helps these plants thrive. If other plants do not produce histidine, it becomes likely that they all produce some other chemical which helps them thrive.
Hence (B) helps us evaluate "what is it that allows this herb to grow in metal-rich soils?"

Answer (B)