OEQ1. The passage is primarily concerned with
A. defending a controversial approach
B. criticizing an accepted view
C. summarizing research findings
D. contrasting competing theories
E. describing an innovative technique
Main ideaFiguring out the authors’ primary concern depends on a careful review of the passage as a whole. The first paragraph identifies the larger question that is the context for the authors’ investigation. The second paragraph presents the part of the question the authors researched, concluding with their unexpected results. The third paragraph explains the importance of these findings in relation to the larger question of the universe’s possible “close.” The authors’ primary purpose in this passage is to summarize the findings of their research.
A. The authors do not discuss approaches to the question they research.
B. The authors mention that their findings do not conform to Kepler’s law, but the passage’s primary focus is on summarizing research findings and not on criticizing any particular view.
C.
Correct. This passage presents a summation of the findings of the authors’ research.
D. The authors do not contrast different theories in this passage.
E. The authors do not discuss new techniques in this passage.
The correct answer is C.Q2. The authors’ study indicates that, in comparison with the outermost regions of a typical spiral galaxy, the region just outside the nucleus can be characterized as having
A. higher rotational velocity and higher luminosity
B. lower rotational velocity and higher luminosity
C. lower rotational velocity and lower luminosity
D. similar rotational velocity and higher luminosity
E. similar rotational velocity and similar luminosity
InferenceIn the second paragraph, the authors observe that outside the bright nucleus of a typical spiral galaxy luminosity falls off rapidly (lines 20–21); the region just outside the nucleus may thus be characterized as having higher luminosity than the outermost regions of a spiral galaxy. Their research finds that the rotational velocity in spiral galaxies either remains constant with increasing distance from the center or increases slightly (lines 27–30). The region just outside the nucleus may thus be characterized as sharing with the outermost regions of a spiral galaxy a similar rotational velocity.
A. This region was expected to have higher rotational velocity, but the research findings did not corroborate this hypothesis; it is correct that the region has higher luminosity.
B. The region does have higher luminosity, but not lower rotational velocity.
C. The region has neither lower luminosity nor lower rotational velocity.
D.
Correct. The region has similar rotational velocity and higher luminosity.
E. The region has similar rotational velocity but higher luminosity.
The correct answer is D.Q3. The authors’ suggestion that “as much as 90 percent of the mass of the universe is not radiating at any wavelength with enough intensity to be detected on the Earth” (lines 34–37) would be most weakened if which of the following were discovered to be true?
A. Spiral galaxies are less common than types of galaxies that contain little nonluminous matter.
B. Luminous and nonluminous matter are composed of the same basic elements.
C. The bright nucleus of a typical spiral galaxy also contains some nonluminous matter.
D. The density of the observable universe is greater than most previous estimates have suggested.
E. Some galaxies do not rotate or rotate too slowly for their rotational velocity to be measured.
ApplicationThe authors’ conclusion about nonluminous matter is based on their study of the rotational velocity of spiral galaxies. If spiral galaxies were found to be atypical of galaxies, then it would be possible that, in those other galaxies, nonluminous matter does not increase as luminous matter decreases. If this were the case, the authors’ conclusion would be based on a sample of galaxies not representative of the whole, and their argument would be seriously weakened.
A.
Correct. The authors’ conclusion assumes that spiral galaxies are typical of all galaxies; information calling that assumption into question weakens the argument.
B. The relation rather than the composition of luminous and nonluminous mass is relevant to the conclusion.
C. Nonluminous mass increases as luminous mass decreases: This finding does not rule out that the nucleus contains some nonluminous mass; the argument is not affected.
D. The density of the observable universe is only a fraction of the density needed to “close” the universe, so even if this density were greater, it is not likely to exceed the density of nonluminous matter.
E. The authors are concerned only with measurable rotational velocity.
The correct answer is A.Q4. It can be inferred from information presented in the passage that if the density of the universe were equivalent to significantly less than three hydrogen atoms per cubic meter, which of the following would be true as a consequence?
A. Luminosity would be a true indicator of mass.
B. Different regions in spiral galaxies would rotate at the same velocity.
C. The universe would continue to expand indefinitely.
D. The density of the invisible matter in the universe would have to be more than 70 times the density of the luminous matter.
E. More of the invisible matter in spiral galaxies would have to be located in their nuclei than in their outer regions.
InferenceAn inference is drawn from stated information. This question refers to the first paragraph, where the authors explain that the critical density of matter needed to brake the expansion and “close” the universe is equivalent to three hydrogen atoms per cubic meter (lines 6–9). If the density is significantly less, then the universe will not “close” but continue to expand indefinitely.
A. The authors’ finding that luminosity is not a true indicator of mass is not derived from the conclusion that the density is less than three hydrogen atoms per cubic meter.
B. The authors’ finding that different regions rotate at similar velocities does not come from the hypothesis about the density of the universe.
C.
Correct. If the critical density needed to “close” the universe is equivalent to three hydrogen atoms per cubic meter, then a density of significantly less than this amount means that the universe will continue its expansion.
D. This statement would be true of the hypothetical “close” of the universe, but if the density is less than three hydrogen atoms per cubic meter, the universe will continue its expansion.
E. This statement cannot be inferred from the hypothesis about the density of the universe.
The correct answer is C.Q5. The authors propose all of the following as possibly contributing to the “missing matter” in spiral galaxies EXCEPT
A. massive black holes
B. small black holes
C. small, dim stars
D. massive stars
E. large planets
Supporting ideasThis question asks the reader to find the list of possible explanations for the “missing” or dark matter that the authors give in the passage and to check that list against the possible answers. Using the process ofelimination will show which answer is not included on the authors’ list. In the final paragraph, the authors write, Such dark matter could be in the form of extremely dim stars of low mass, of large planets like Jupiter, or of black holes, either small or massive (lines 37–40).
A. The authors include massive black holes.
B. The authors include small black holes.
C. The authors include small, dim stars.
D.
Correct. The authors do not include massive stars in their list of possible explanations for “missing matter.”
E. The authors include large planets.
The correct answer is D.
Apr 28
12 Apr 2019, 08:18
,Could you share your thoughtful insight on question? 
