請教 GWD 6-Q40 感謝

97.    (28634-!-item-!-188;#058&003060)  (GWD 6-Q40)

It is theoretically possible that bacteria developed on Mars early in its history and that some were carried to Earth by a meteorite.  However, strains of bacteria from different planets would probably have substantial differences in protein structure that would persist over time, and no two bacterial strains on Earth are different enough to have arisen on different planets.  So, even if bacteria did arrive on Earth from Mars, they must have died out.

The argument is most vulnerable to which of the following criticisms?

A. It fails to establish whether bacteria actually developed on Mars.

B. It fails to establish how likely it is that Martian bacteria were transported to Earth.

C. It fails to consider whether there were means other than meteorites by which Martian bacteria could have been carried to Earth.

D. It fails to consider whether all bacteria now on Earth could have arisen from transported Martian bacteria.

E. It fails to consider whether there could have been strains of bacteria that originated on Earth and later died out.

ANS: D  想請問E選項~~錯在哪裡?  雖然感覺D選項比較強烈~但是E感覺也有相關~~感謝大家講解~~! 多謝~~!

ANS: D  想請問E選項~~錯在哪裡?  雖然感覺D選項比較強烈~但是E感覺也有相關~~感謝大家講解~~! 多謝~~!

h5614已经分析的很清楚了。我稍微加点补充免得有些人还是看不太明白。

要去质疑这个理论只需要证明这一点：火星的bacteria曾经达到过地球而且现在还存活着。有两条路可以走：1）当前的bacteria都是从火星上来的 2）当前存在的bacteria部分是地球原生，部分是从火星上来的。要支持2）则需要质疑题干中的假设即不同星球上的bacteria其strain是肯定不一样的，也就是要证明火星和地球上的bacteria的strain是可以一样的。

看选项D)就是走的路1），但是没有其他选项是走路2）的。

再来看看选项E)有什么问题。

E) It fails to consider whether there could have been strains of bacteria that originated on Earth and later died out.

隐含的意思是“地球上曾经有不同strains的bacteria共存过，或者即使没有共存过那在不同阶段产生bacteria的strains可能不同”。这些可能性都无法推断出地球上的bacteria和火星上的可以有相同的strains。所以推理过程会产生断裂而无法继续。