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 processes.
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
OA Answer : E
My question : when i saw the word "controversy", i immediately crossed this answer out because nowhere in the passage is it described to be a controversy per se. Its just support and counter arguements in the essay, but nowwhere really a controversy. Hence i chose B
Thoughts on why E is the OA answer ?
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 processes.
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
OA Answer : E
My question : when i saw the word "controversy", i immediately crossed this answer out because nowhere in the passage is it described to be a controversy per se. Its just support and counter arguements in the essay, but nowwhere really a controversy. Hence i chose B
Thoughts on why E is the OA answer ?
