GWD6-Q40 的E选项想不明白

fuchengxuan

GWD6-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.

D明白，我只是不知道为啥E不对。
条件：1 不同星球上的B不同。
2 但是地球上的B相同
结论：即使有来自火星的B，也都死光了。
而E是说地球上曾经有来自地球的B，但是后来死光了。 所以这就不能推出来（如果有）来自火星上的B一定都死光了啊。
为什么E不对呢？...

fuchengxuan

顶顶。。