In 1994, a team of scientists led by David McKay

Question

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, 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 molecules--complex, carbonbased compounds--form the basis for terrestrial life. The organic molecules found in ALH84001 are polycyclic aromatic hydrocarbons, or PAH's. When microbes die, their organic material often decays into PAH's.

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 resulted form terrestrial contamination. However, McKay's team has demonstrated that the concentration of PAH's increases as one looks deeper into ALH84001, contrary to what one would 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, 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. 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 processe.   Q1. The primary purpose of the passage is to 
 
A. describe new ways of studying the possibility that life once existed on Mars
B. revise a theory regarding the existence of life on Mars in light of new evidence
C. reconcile conflicting viewpoints regarding the possibility that life once existed on Mars
D. evaluate a recently proposed argument concerning the origin of ALH84001
E. describe a controversy concerning the significance of evidence from ALH84001 1 
 In the first paragraph, the passage indicates that a research team found that a Martian meteorite in Antarctica contains compelling evidence that life existed on Mars. The rest of the passage then describes arguments by skeptics against the research team’s conclusion together with the research team’s rebuttals to the skeptics’ arguments. E correct since The passage describes opposing arguments about whether ALH84001 suggests life ever existed on Mars.

Q2. The passage asserts which of the following about the claim that ALH84001 originated on Mars? 
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. 2 
 In stating that scientists generally agree ALH84001 originated on Mars, the passage indicates there is no real controversy on this matter.

Q3. The passage suggests that the fact that ALH84001 has been on Earth for 13,000 years has been used by some scientists to support which of the following claimsabout ALH84001? 
A. ALH84001 may not have originated on Mars.
B. ALH84001 contains PAHs that are the result of nonbiological processes.
C. ALH84001 may not have contained PAHs when it landed on Earth.
D. The organic molecules found in ALH84001 are not PAHs.
E. The organic molecules found in ALH84001 could not be the result of terrestrial contamination. 3 
 In the second paragraph, the passage presents various skeptics’ arguments about whether the PAHs in ALH84001 originated on Mars. In lines 15–19, the passage indicates that some scientists see the fact that ALH84001 has been on Earth for 13,000 years as raising the possibility that the PAHs in ALH84001 resulted from terrestrial contamination or in other words that it did not contain PAHs when it landed on Earth. In C - The passage indicates that some scientists believe that the PAHs in ALH84001 may have been transferred to it during its 13,000 years on Earth.

Q4. The passage suggests that if a meteorite contained PAHs that were the result of terrestrial contamination, then one would expect which of the following to be true? 
A. The meteorite would have been on Earth for more than 13,000 years.
B. The meteorite would have originated from a source other than Mars.
C. The PAHs contained in the meteorite would have originated from nonbiological processes.
D. The meteorite would contain fewer PAHs than most other meteorites contain.
E. The PAHs contained in the meteorite would be concentrated toward the meteorite’s surface. 4 
 According to the passage, some scientists believe that because ALH84001 has been on Earth for as long as 13,000 years, any PAHs contained in it may have been transferred from the Earth, a process the passage describes as terrestrial contamination (line 19). The passage also indicates that if terrestrial contamination occurred with ALH84001, then, contrary to the findings of McKay’s team that showed PAH concentrations increasing as one looks deeper into ALH84001 (lines 21–22), the PAHs would be expected to be concentrated more toward the outer parts, or surface, of ALH84001.

Q5. Which of the following best describes the function of the last sentence of the first paragraph? 
A. It identifies a possible organic source for the PAHs found in ALH84001.
B. It describes a feature of PAHs that is not shared by other types of organic molecules.
C. It explains how a characteristic common to most meteorites originates.
D. It suggests how the terrestrial contamination of ALH84001 might have taken place.
E. It presents evidence that undermines the claim that life once existed on Mars. 5 
 The first paragraph begins by establishing that McKay’s team believes that the PAHs found in ALH84001 provide compelling evidence that life existed on Mars. To explain this, the passage indicates that PAHs are a type of organic molecules, which form the basis for life. Furthermore, to connect PAHs to possible life on Mars, the final sentence of the first paragraph indicates that one source of PAHs is the decay of dead microbes.

Q6. The passage suggests that McKay’s team would agree with which of the following regarding the PAHs produced by nonorganic processes? 
A. These PAHs are not likely to be found in any meteorite that has been on Earth for 13,000 years or more.
B. These PAHs are not likely to be found in any meteorite that originated from Mars.
C. These PAHs are not likely to be produced by star formation.
D. These PAHs are likely to be found in combinations that distinguish them from the PAHs produced by organic processes.
E. These PAHs are likely to be found in fewer meteorites than the PAHs produced by organic processes. 6 
 The passage indicates in lines 11–13 that the organic molecules found in ALH84001 are PAHs. In lines 23–27, skeptics of McKay’s team’s findings point out that processes unrelated to organic life, including star formation, can produce PAHs. In the final sentence of the passage, McKay’s team notes that the type of PAHs found in ALH84001 are more similar to those produced by organic processes than to those produced by nonorganic processes.   
 Source : Verbal Official Guide 2018

Bunuel · Answer

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In 1994, a team of scientists led by David McKay

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