请教各位一道GWD的阅读题！

ss100404

GWD-TN-2GWD3-Q5 to Q7:          In 1994, ateam of scientists led by David Mckay began studying the meteorite ALH84001,which had been discovered in Antarctica in1984. Two years later, the McKay team announced that ALH84001, which scientistsgenerally agree originated on Mars, contained compelling evidence that lifeonce existed on Mars. This evidence includes the discovery of organic moleculesin ALH84001, the first ever found in Martian rock.
Organic molecules—complex, carbonbased compounds—form thebasis for terrestrial life.  The organicmolecules found in ALH84001 are polycyclic aromatic hydrocarbons, orPAH’s.  When microbes die, their organic materialoften decays into PAH’s.
        Skepticism about the McKay team’sclaim remains, however.  For example,ALH84001 has been on earth for 13,000 years, suggesting to some scientists thatits PAH’s might have resulted form terrestrial contamination. However, McKay’steam has demon stated that the concentration of PAH’s increases as one looksdeeper into ALH84001, contrary to what one would expect from terrestrialcontamination. The skeptic’s strongest argument, however, is that processesunrelated to organic life can easily produce all the evidence found by McKay’ steam, including PAH’s.  For example, starformation produces PAH’s.  Moreover, PAH’s frequentlyappear in other meteorites, and no one attributes their presence to lifeprocesses. Yet McKay’s team notes that the particular combination of PAH’s inALH84001 is more similar to the combinations produced by decaying organismsthan to those originating form nonbiological processes.


Q5:The passage asserts which of the following about the claim that ALH84001originated on Mars?
A.     Itwas initially proposed by the McKay team of scientists.

B.     It is not a matter of widespread scientific dispute.
C.     Ithas been questioned by some skeptics of the McKay team’swork.
D.     Ithas been undermined by recent work on PAH’s.
E.      Itis incompatible with the face that ALH84001 has been on Earth for 13,000 years.


答案是B，有哪位大神能帮我解释一下么~~感激不尽~

yangrryq

定位：which scientistsgenerally agree originated on Mars,
必须是b.大家都同意就不是一个广泛的争议。