Supernovas in the Milky Way are the likeliest source for most of the

Question

Supernovas in the Milky Way are the likeliest source for most of the cosmic rays reaching Earth. However, calculations show that supernovas cannot produce ultrahigh-energy cosmic rays (UHECRs), which have energies exceeding 1018 electron volts. It would seem sensible to seek the source of these in the universe’s most conspicuous energy factories: quasars and gamma-ray bursts billions of light-years away from Earth. But UHECRs tend to collide with photons of the cosmic microwave background—pervasive radiation that is a relic of the early universe. The odds favor a collision every 20 million light-years, each collision costing 20 percent of the cosmic ray’s energy. Consequently, no cosmic ray traveling much beyond 100 million light-years can retain the energy observed in UHECRs.    1 
 1. It can be inferred that the author of the passage would agree with which of the following about the origin of UHECRs that reach Earth?

I. The origin is something other than supernovas in the Milky Way.
II. The origin is most likely something other than very distant quasars or gamma-ray bursts.
III. The origin is most likely no more than a little over 100 million light-years away from Earth.

A. I only
B. III only
C. I and II only
D. I and III only
E. I, II, and III

2 
 2. In the context of the author’s argument, the last sentence performs which of the following functions?

A. It explains a criterion that was employed earlier in the argument.
B. It shows that an apparently plausible position is actually self-contradictory.
C. It is a conclusion drawn in the course of refuting a potential explanation.
D. It overturns an assumption on which an opposing position depends.
E. It states the main conclusion that the author is seeking to establish.

RC Butler 2022  -  Practice Two RC Passages Everyday.   
Passage # 280 Date: 13-Jul-2022
 This question is a part of RC Butler 2022 .  Click here for Details

sunitapandey · Answer

1. It can be inferred that the author of the passage would agree with which of the following about the origin of UHECRs that reach Earth?

I. The origin is something other than supernovas in the Milky Way. - The passage says that supernova cannot be the source of such massive energy and then says that it has to be quasar and gamma bursts. So we can infer that the source of UHECRs cannot be supernova 
II. The origin is most likely something other than very distant quasars or gamma-ray bursts.-- The passage says the opposite.
III. The origin is most likely no more than a little over 100 million light-years away from Earth.The passage says that the most likely source - Quasar and gamma bursts are billions of light year away.

A. I only

sunitapandey · Answer

2. In the context of the author’s argument, the last sentence performs which of the following functions?

A. It explains a criterion that was employed earlier in the argument.-- It does not explain any criteria
 B. It shows that an apparently plausible position is actually self-contradictory. - Correct As it says if a source is 100 million light years away it cannot retain sufficient energy. 
C. It is a conclusion drawn in the course of refuting a potential explanation. -- There is no refusing of any potential explanation
D. It overturns an assumption on which an opposing position depends. - there is no assumption that is getting proved wrong
E. It states the main conclusion that the author is seeking to establish. - B wins over this

BLTN · Answer

Dear sunitapandey , I rejected the "II" option by the same reason, but it was wrong to do so. Passage states: It would seem sensible to seek the source of these in the universe’s most conspicuous energy factories: quasars and gamma-ray bursts billions of light-years away from Earth . The only quibble is distance. Because later, passage states that Consequently, no cosmic ray traveling much beyond 100 million light-years can retain the energy observed in UHECRs . So, we can deduce that if within the distance > 100M light-years there are NO cosmic rays, then within more far distance, such as billions of light-years away, there are no NO cosmic rays also. For the "III." option, author asserts that Consequently, no cosmic ray traveling much beyond 100 million light-years "Much beyond" does not counter the phrase "no more than a little over 100 million" Hope it helps someone

mahmudul55 · Answer

How is the option 2 of the first question correct?? Does not it mean that something to be far distance from quasars or gamma-ray bursts.

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GMATCoachBen · Answer

mahmudul55

II. The origin is most likely something  other than very distant  quasars or gamma-ray bursts.

This is supported, because the author's conclusion in the final sentence says that the origin is NOT "very distant" (note that from the context, "very distant" is referring to "billions of light-years away", in the 3rd sentence): 
"Consequently, no cosmic ray traveling much beyond 100 million light-years can retain the energy observed in UHECRs."

Note that the 3rd and 4th sentences also show doubt about the origin being very distant quasars or gamma-ray bursts:
"It would  SEEM  sensible to seek the source of these in the universe’s most conspicuous energy factories: quasars and gamma-ray bursts billions of light-years away from Earth.  BUT  UHECRs tend to collide with photons of the cosmic microwave background—pervasive radiation that is a relic of the early universe."

"Seem" and "But" are very helpful language clues. Contrast Markers, including "But" and "However", are very common and important to notice, as they often signal key points.

mahmudul55 · Answer

In the passage saying that the origin of UECRs which wave reach in the earth is less than or equal 100 million light year distance.
But i do not understand properly the 2nd answer choice of 1st question. 
Is there contrasting between "very distance quasars and gamma-ray bursts and something other" for the origin of UECRs??

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GMATCoachBen · Answer

mahmudul55  First, lets make sure we fully understand statement II:

"II. The origin is most likely  something other than  very distant quasars or gamma-ray bursts."

"something other than" means NOT, so this statement means that the origin is likely NOT the "very distant quasars", but rather something else.

Note that "very distant" is referring to the 3rd sentence: "quasars and gamma-ray bursts BILLIONS of light-years away from Earth."

Then, you're correct that the author uses contrasting language and explains why this is unlikely. Yes, the final sentence supports your quote below:

sunitapandey · Answer

Thanks for elaborating

tkorzhan18 · Answer

@Sajjad1994m , can you please explain what explanation the last sentence is refuting for q2?

Sajjad1994 · Answer

Official Explanation

2. In the context of the author’s argument, the last sentence performs which of the following functions?

Explanation

The  last sentence  in the passage serves to reinforce a limitation on the propagation distance of ultrahigh-energy cosmic rays (UHECRs) due to their interactions with photons from the cosmic microwave background (CMB). Specifically, it states that no cosmic ray traveling much beyond 100 million light-years can retain the energy observed in UHECRs. Let's analyze each option to determine the function of this sentence in the context of the author's argument:

A.  is incorrect because the sentence doesn't explain a criterion employed earlier; instead, it presents a conclusion based on the limitations imposed by interactions with the cosmic microwave background.

B.  doesn't accurately describe the function of the sentence. The sentence doesn't reveal a contradiction within a particular position; rather, it emphasizes a limitation on the propagation of UHECRs due to their interactions with the CMB.

C.   correctly identifies the function of the sentence. The sentence concludes the discussion by highlighting a limitation that undermines the idea of quasars and gamma-ray bursts billions of light-years away being the source of UHECRs, refuting this potential explanation due to the loss of energy over long distances.

D.  doesn't accurately describe the function of the sentence. The sentence doesn't directly overturn an assumption; rather, it presents a conclusion based on the limitations imposed by interactions with the cosmic microwave background.

E.  is incorrect because the sentence doesn't represent the main conclusion of the argument. It serves to highlight a limitation in the propagation of UHECRs rather than encapsulating the overall argument's main point.

Answer: C

Supernovas in the Milky Way are the likeliest source for most of the

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Supernovas in the Milky Way are the likeliest source for most of the

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