[求助]GWD28－28

mimixiaxia

up

mimixiaxia

up

qianrene

http://forum.chasedream.com/dispbbs.asp?boardid=24&id=185888&star=4#185888

lichabrend

up

pengzq

question :

a hypothesis: the herb’s high histidine production is what allows it to grow in metal-rich soils

C. others of the closely related group of plants are also found to produce histidine in large quantities - Many guys picked up this option. Let me tell you why this is NOT the correct answer. The sentence simply indicates that other closely related group of plants also produce histidine in large quantities. This statement might be true, but it does not prove that histidine is indeed responsible for herb's growth in metal-rich soil. It might be possible that some other element is responsible for the growth of plants, which is not yet being discovered. So this statement does not provide any support to the hypothesis.
E. the concentration of histidine in the growing herb declines as the plant approaches maturity - BINGO!!!! Read the hypothesis again. It says that the histidine helps the plants to GROW in the metal-rich soil. This is the only option which talks about growth of the herb. If the histidine is only helping the plants to grow, then logically it is not even required once the plant is fully grown. Also, this is the only BEST answer we have.

e

gmat928

这个题我选了D，看答案是C，看完大N们的讨论觉得该选C，但仔细一想，还应该是D。太纠结了。。。

C有个问题，有可能其他每种植物都有自己的看家本领对抗metals ，而不是因为他们有histidine。只是因为他们同属于one of a group of closely related plants，所以才都 produces large amounts of histidine。不能证明herb的histidine是他对抗metals 的原因，因为herb也可能有除histidine之外的独门绝技对抗metals。

小毛钢琴六级，被保送到重点中学。邻居其他被保送的小学生也都钢琴六级，所以小毛被保送的原因是因为他钢琴六级。
这种推理有问题，因为实际上被保送的根本原因可能是因为他连续三年都是三好学生。

本题提干里说histidine在实验室里（test-tube solutions）能钝化metals，但这句话不能证明在histidine实际生长土壤中（metal-rich soils）也能钝化metals。
hypothesis正是histidine production is what allows it（herb） to grow in metal-rich soils

中间的gap是：histidine在实际生长土壤中（metal-rich soils）也能钝化metals。

而D说histidine不但在实验室里能钝化metals，在实际生长土壤中也能完成这一动作，因为其他不能钝化metals的植物能在“曾被herb的histidine钝化过的土壤中”生长。这正好support hypothesis：herb’ s high histidine production is what allows it to grow in metal-rich soils

其他选项错误原因：
A 根茎叶花都含有histidine无法证明histidine能怎样，根茎叶花含还都含有水分呢，不能因此证明水能怎样。
B low level of production of other amino acids是无关内容
C 上面说过了
D 正确
E histidine随着生长减少也无法证明histidine能怎样，水分随着生长也会减少，不能因此证明水能怎样。

songsimiao

up

charlesyu

我也选了D，同意55楼推理过程！
做AA作文时，如果出现C和E这样的论证，都应该是驳斥的对象吧？
C，类似的咋样就能说明也咋样？
E，同一个时期内，有另一个变化伴随发生，就能证明互相有因果关系？