Reading Comprehension

试题详情

文章:

Line In 1994, a team of scientists led by David McKay
began studying the meteorite ALH84001, which had
been discovered in Antarctica in 1984. Two years
later, the McKay team announced that ALH84001,
(5) which scientists generally agree originated on Mars,
contained compelling evidence that life once
existed on Mars. This evidence includes the
discovery of organic molecules in ALH84001, the
first ever found in Martian rock. Organic
(10) molecules—complex, carbon-based compounds—
form the basis for terrestrial life. The organic
molecules found in ALH84001 are polycyclic
aromatic hydrocarbons, or PAHs. When microbes
die, their organic material often decays into PAHs.
(15) 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 PAHs might have resulted
from terrestrial contamination. However, McKay’s
(20) team has demonstrated that the concentration of
PAHs increases as one looks deeper into
ALH84001, contrary to what one would expect from
terrestrial contamination. The skeptics’ strongest
argument, however, is that processes unrelated to
(25) organic life can easily produce all the evidence
found by McKay’s team, including PAHs. For
example, star formation produces PAHs. Moreover,
PAHs frequently appear in other meteorites, and no
one attributes their presence to life processes. Yet
(30) McKay’s team notes that the particular combination
of PAHs in ALH84001 is more similar to the
combinations produced by decaying organisms than
to those originating from nonbiological processes.

题目:

The passage asserts which of the following about the claim that ALH84001 originated on Mars?

选项:

A、It was initially proposed by the McKay team of scientists.
B、It is not a matter of widespread scientific dispute.
C、It has been questioned by some skeptics of the McKay team’s work.
D、It has been undermined by recent work on PAHs.
E、It is incompatible with the fact that ALH84001 has been on Earth for 13,000 years.

答案:

B
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