GWD28-Q28,一道纠结，C or D,我搜索过了，但是没有能说服我的

雪梦儿

GWD28-Q28,一道纠结的CR，值得讨论下

28. GWD28-Q28:
Which of the following most logically completes the 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.  Agronomists studying the herb have discovered that it produces large amounts of histidine, an amino acid that, in test-tube solutions, renders these metals chemically inert.（惰性）  ossibly, therefore, the herb’s high histidine production is what allows it to grow in metal-rich soils, a hypothesis that would gain support if ______.
A.    histidine is found in all parts of the plant—roots, stem, leaves, and flowers
B.    the herb’s high level of histidine production is found to be associated with an unusually low level of production of other amino acids
C.    ！others of the closely related group of plants are also found to produce histidine in large quantities
D.    cultivation of the herb in soil with high concentrations of the metals will, over an extended period, make the soil suitable for plants to which the metals are toxic
E.    the concentration of histidine in the growing herb declines as the plant approaches maturity

sdcar2010

Premise:
1)  A group of closely related plants that thrive in soil with high concentrations of metals.
2)  A certain cultivated herb is one of a group of closely related plants.
3)  The herb produces large amounts of histidine.

Conclusion:
The herb's high histidine production is what allows it to grow in metal-rich soils.

Strengthener:
Other members of the same closely related group of plants are also found to produce histidine in large quantities. These plants thrive in soil with high concentrations of metals.

This is causation vs. correlation.  A closely related group of plants survives the high concentration of metals in soil.  The stimulus provides a hypothesis that the production of histidine in one herb from this group of plants is required for the herd to detoxify the metal.  If other plants from the same closely related group are also found to produce histidine and we already know these plants can deal with the metals, then it is more likely the stated hypothesis is right.

雪梦儿

可我怎么觉得C无关呢，其他的相关plant怎么样，产不产h，好像不会有影响啊。。。

雪梦儿

Premise:
1)  A group of closely related plants that thrive in soil with high concentrations of metals.
2)  A certain cultivated herb is one of a group of closely related plants.
3)  The herb produces large amounts of histidine.

Conclusion:
The herb's high histidine production is what allows it to grow in metal-rich soils.

Strengthener:
Other members of the same closely related group of plants are also found to produce histidine in large quantities. These plants thrive in soil with high concentrations of metals.

This is causation vs. correlation.  A closely related group of plants survives the high concentration of metals in soil.  The stimulus provides a hypothesis that the production of histidine in one herb from this group of plants is required for the herd to detoxify the metal.  If other plants from the same closely related group are also found to produce histidine and we already know these plants can deal with the metals, then it is more likely the stated hypothesis is right.

-- by 会员 sdcar2010 (2011/7/24 19:39:20)

再看一边解释我觉得我可以理解C对了，因为大家都具有同一种性质，而大家都可以在这种土壤生存，所以就应该是这种性质导致了可以在这种土壤生存，但是D为什么不可以呢？
D的话说明了，那个产生的h将土壤里的metal中和了，所以就别的生物就可以生存了。。。这样推理哪里不对呢？

jameshzd

这里有个 gap，thrive 是修饰a group of closely related plants ，而 A certain cultivated herb只是其中的一员，现在文中 举出 这个certain cultivated herb能产出  large amounts of histidine，因此得出结论 large amounts of histidine 是能grow in metal-rich soils 的原因，这样就有了一个gap，这一个 group都可以在这个metal-rich soils 里面存活，但是文章只列举了它里面的一员有这个特征，从而推出这个特征导致可以在metal-rich soils 里面存活，C这号填补了其他成员也具有这个特征，而D中，没有任何信息说h 可以和metal 中和啊，只说h 能是plants 存活，没说可以把metal中和。

deifica

为什么不选E。。我悲催地问。。。有没有筒子和我一样觉得选E

jameshzd

E 是无关啊，你怎么想的列？

deifica

http://www.urch.com/forums/gmat-critical-reasoning/108597-certain-cultivated-herb.html 还好老美有同意我的。。

deifica

E 是无关啊，你怎么想的列？

-- by 会员 jameshzd (2011/7/24 22:51:23)

这道题是有争议的，我会选E，至于详细解释可以参考我的那个Link,表示同意那个老美的思路（第一个回帖），因为C只是说分泌大量的histine并没有说明为什么这种histine就是植物在deterimental environment生长的原因

deifica

可我怎么觉得C无关呢，其他的相关plant怎么样，产不产h，好像不会有影响啊。。。

-- by 会员 雪梦儿 (2011/7/24 19:45:00)

~~我们同一战线~~挖哈哈