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标题: 请教 GWD5-40 [打印本页]

作者: lguo1 时间: 2006-10-6 16:19
标题: 请教 GWD5-40

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?

It
fails to establish whether bacteria actually developed on Mars.
It
fails to establish how likely it is that Martian bacteria were transported
to Earth.
It
fails to consider whether there were means other than meteorites by which
Martian bacteria could have been carried to Earth.
It
fails to consider whether all bacteria now on Earth could have arisen from
transported Martian bacteria.
It
   fails to consider whether there could have been strains of bacteria that
   originated on Earth and later
   died out.

The correct answer is D.

My question is how about E? Both D and E seem similar: The Martian bacteria survived and the earth bacteria die out.

Thanks!

作者: allfar 时间: 2006-10-6 16:41

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

这是E的问题.

D中说,如果所有细菌都是来此火星的话.....

那么显然就不会和地球的有很大区别.正好削弱了结论,来到地球的细菌都"挂"了.~~~~

作者: lguo1 时间: 2006-10-6 16:49
Got it. E is irrelavant, since we're not talking about Earth bacteria here at all.

Thank you very much!

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