请教GWD3-Q6

GWD3-Q5 to Q7:

      In 1994, a team of scientists led

       by David Mckay began studying the

       meteorite ALH84001, which had been

Line       discovered in Antarctica in 1984.

  (5)      Two years later, the McKay team

announced that ALH84001, which

scientists generally agree originated

on Mars, contained compelling evi-

dence that life once existed on Mars.

 (10)      This evidence includes the discovery

of organic molecules in ALH84001,

the first ever found in Martian rock.

Organic molecules—complex, carbon-

based compounds—form the basis for

 (15)      terrestrial life.  The organic molecules

found in ALH84001 are polycyclic aro-

matic hydrocarbons, or PAH’s.  When

microbes die, their organic material

often decays into PAH’s.

 (20)           
                        Skepticism about the McKay team’s

       claim remains, however.  For example,

       ALH84001 has been on earth for

13,000 years, suggesting to some

scientists that its PAH’s might have

 (25)      resulted form terrestrial contamination.

However, McKay’s team has demon-

strated that the concentration of PAH’s

increases as one looks deeper into

ALH84001, contrary to what one would

 (30)      expect from terrestrial contamination.

The skeptic’s strongest argument,

however, is that processes unrelated

       to organic life can easily produce all

the evidence found by McKay’ steam,

 (35)
                       including PAH’s.  For example, star

formation produces PAH’s.  Moreover,

PAH’s frequently appear in other

meteorites, and no one attributes

      their presence to life processes.

 (40)     Yet McKay’s team notes that the

particular combination of PAH’s

in ALH84001 is more similar to the

combinations produced by decaying

organisms than to those originating

form nonbiological processes.

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The primary purpose of the passage is to

1. describe new ways of studying the possibility that life once existed on Mars
2. revise a theory regarding the existence of life on Mars in light of new evidence
3. reconcile conflicting viewpoints regarding the possibility that life once existed on Mars(E)
4. evaluate a recently proposed argument concerning the origin of ALH84001
5. describe a controversy concerning the significance of evidence from ALH84001

文章中似乎没有提到significance of evidence

争论的焦点是the possibility that life once existed on Mars

C中的reconcile我觉得用的的确也不对

但请问一下这里的significance应该怎么理解?

Two years later, the McKay team announced that ALH84001, which scientists generally agree originated
            on Mars, contained compelling evidence that life once existed on Mars.

请问(B)不对是因为文章中并没有提供什么new evidence吗???

我認為爭論的焦點應該是 ALH84001上的PAH之可信度。

批評者認為1.ALH84001在地球待了很久，怎麼知道PAH一定從火星來？畢竟PAH是細胞死亡的殘餘（這樣翻對不對...），所以選E

C的話，爭論重點已經不在火星有沒有生物，而是在辯論他們從ALH84001找到的證據有沒有可信度。故錯

第一次回應，解讀有錯請各位NN指教