According to the theory of gravitation, every particle of matter in

Question

According to the theory of gravitation, every
particle of matter in the universe attracts every other
particle with a force that increases as either the mass of
the particles increases, or their proximity to one
  (5)   another increases, or both. Gravitation is believed to
shape the structures of stars, galaxies, and the entire
universe. But for decades cosmologists (scientists who
study the universe) have attempted to account for the
finding that at least 90 percent of the universe seems to
  (10)   be missing: that the total amount of observable
matter—stars, dust, and miscellaneous debris—does
not contain enough mass to explain why the universe is
organized in the shape of galaxies and clusters of
galaxies. To account for this discrepancy, cosmologists
  (15)   hypothesize that something else, which they call “dark
matter,” provides the gravitational force necessary to
make the huge structures cohere.

What is dark matter? Numerous exotic entities
have been postulated, but among the more attractive
  (20)   candidates—because they are known actually to
exist—are neutrinos, elementary particles created as a
by-product of nuclear fusion, radioactive decay, or
catastrophic collisions between other particles.
Neutrinos, which come in three types, are by far the
  (25)   most numerous kind of particle in the universe;
however, they have long been assumed to have no
mass. If so, that would disqualify them as dark matter.
Without mass, matter cannot exert gravitational force;
without such force, it cannot induce other matter to
  (30)   cohere.

But new evidence suggests that a neutrino does
have mass. This evidence came by way of research
findings supporting the existence of a long-theorized
but never observed phenomenon called oscillation,
  (35)   whereby each of the three neutrino types can change
into one of the others as it travels through space.
Researchers held that the transformation is possible
only if neutrinos also have mass. They obtained
experimental confirmation of the theory by generating
  (40)   one neutrino type and then finding evidence that it had
oscillated into the predicted neutrino type. In the
process, they were able to estimate the mass of a
neutrino at from 0.5 to 5 electron volts.

While slight, even the lowest estimate would yield
  (45)   a lot of mass given that neutrinos are so numerous,
especially considering that neutrinos were previously
assumed to have no mass. Still, even at the highest
estimate, neutrinos could only account for about
20 percent of the universe’s “missing” mass.
  (50)   Nevertheless, that is enough to alter our picture of the
universe even if it does not account for all of dark
matter. In fact, some cosmologists claim that this new
evidence offers the best theoretical solution yet to the
dark matter problem. If the evidence holds up, these
  (55)   cosmologists believe, it may add to our understanding
of the role elementary particles play in holding the
universe together.    1 
 1. Which one of the following most accurately expresses the main idea of the passage?

(A) Although cosmologists believe that the universe is shaped by gravitation, the total amount of observable matter in the universe is greatly insufficient to account for the gravitation that would be required to cause the universe to be organized into galaxies.
(B) Given their inability to account for more than 20 percent of the universe’s “missing” mass, scientists are beginning to speculate that our current understanding of gravity is significantly mistaken.
(C) Indirect evidence suggesting that neutrinos have mass may allow neutrinos to account for up to 20 percent of dark matter, a finding that could someday be extended to a complete solution of the dark matter problem.
(D) After much speculation, researchers have discovered that neutrinos oscillate from one type into another as they travel through space, a phenomenon that proves that neutrinos have mass.
(E) Although it has been established that neutrinos have mass, such mass does not support the speculation of cosmologists that neutrinos constitute a portion of the universe’s “missing” mass.

2 
 2. Which one of the following titles most completely and accurately expresses the contents of the passage?

(A) “The Existence of Dark Matter: Arguments For and Against”
(B) “Neutrinos and the Dark Matter Problem: A Partial Solution?”
(C) “Too Little, Too Late: Why Neutrinos Do Not Constitute Dark Matter”
(D) “The Role of Gravity: How Dark Matter Shapes Stars”
(E) “The Implications of Oscillation: Do Neutrinos Really Have Mass?”

3 
 3. Based on the passage, the author most likely holds which one of the following views?

(A) Observable matter constitutes at least 90 percent of the mass of the universe.
(B) Current theories are incapable of identifying the force that causes all particles in the universe to attract one another.
(C) The key to the problem of dark matter is determining the exact mass of a neutrino.
(D) It is unlikely that any force other than gravitation will be required to account for the organization of the universe into galaxies.
(E) Neutrinos probably account for most of the universe’s “missing” mass.

4 
 4. As described in the last paragraph of the passage, the cosmologists’ approach to solving the dark matter problem is most analogous to which one of the following?

(A) A child seeking information about how to play chess consults a family member and so learns of a book that will instruct her in the game.
(B) A child seeking to earn money by delivering papers is unable to earn enough money for a bicycle and so decides to buy a skateboard instead.
(C) A child hoping to get a dog for his birthday is initially disappointed when his parents bring home a cat but eventually learns to love the animal.
(D) A child seeking money to attend a movie is given some of the money by one of his siblings and so decides to go to each of his other siblings to ask for additional money.
(E) A child enjoys playing sports with the neighborhood children but her parents insist that she cannot participate until she has completed her household chores.

5 
 5. The author’s attitude toward oscillation can most accurately be characterized as being

(A) satisfied that it occurs and that it suggests that neutrinos have mass
(B) hopeful that it will be useful in discovering other forms of dark matter
(C) concerned that it is often misinterpreted to mean that neutrinos account for all of dark matter
(D) skeptical that it occurs until further research can be done
(E) convinced that it cannot occur outside an experimental setting

6 
 6. Which one of the following phrases could replace the word “cohere” at line 30 without substantively altering the author’s meaning?

(A) exert gravitational force
(B) form galactic structures
(C) oscillate into another type of matter
(D) become significantly more massive
(E) fuse to produce new particles

7 
 7. The passage states each of the following EXCEPT:

(A) There are more neutrinos in the universe than there are non-neutrinos.
(B) Observable matter cannot exert enough gravitational force to account for the present structure of the universe.
(C) Scientific experiments support the theory of neutrino oscillation.
(D) Neutrinos likely cannot account for all of the universe’s “missing” mass.
(E) Dark matter may account for a large portion of the universe’s gravitational force.

Deadpool3 · Answer

Dear Experts,

Could you please explain How option C is correct and D is incorrect?

1. Which one of the following most accurately expresses the main idea of the passage?

(C)  Indirect evidence suggesting that neutrinos have mass may allow neutrinos to account for up to 20 percent of dark matter , a finding  that could someday be extended to a complete solution of the dark matter problem . -> I understand that the green highlighted is correct, but I am not able to understand the red highlighted in this option. I know that in the passage it is mentioned that it will add a lot to the current understanding, but I am not able to understand that how it leaped to the maybe someday this will help to extend to complete solution.

(D) After much speculation, researchers have discovered that neutrinos oscillate from one type into another as they travel through space, a phenomenon that proves that neutrinos have mass. ->  I believe that the main point is that Neutrinos have mass that help resolves the black matter problem.

Sajjad1994 · Answer

Explanation

6. Which one of the following phrases could replace the word “cohere” at line 30 without substantively altering the author’s meaning?

Explanation

The author says that neutrinos must have mass to exert a gravitational force. He also says that gravitational force is what causes matter to form itself into planets, solar systems, and galaxies. So if we replace the word  “cohere”  with something that means,  “stick together in the form of planets, etc,”  then we’ll be on the right track.  (B)  is pretty close to this.

(A) —neutrinos don’t induce other matter to have gravitational force. All matter has gravitational force, as  line 2  says.

(C)  is a distortion. Oscillation is a property of neutrinos; it is not discussed as a property of any other type of matter.

(D) —particles other than neutrinos changing mass is well outside the scope of the passage.

(E) —fusion is discussed as a way neutrinos are formed, not as an effect of neutrinos.

Answer: B

MBAB123 · Answer

Deadpool3 , I'm no expert but see this helps

Option C - Adding to the current understanding is similar to someday extended to a complete solution of the dark matter . Obviously, these 2 phrases are not exactly the same, bu they give the same idea - the idea that the said discovery is a positive step towards the mail goal. Option D - This option is wrong for the reason that you pointed out. This option suggests that the passage revolvers around the discovery for oscillation. Oscillation is just one aspect of the passage. D does not consider a lot of points/questions that surround the main idea of the passage. So what if neutrinos have mass? What are you trying to do by stating that it has mass? The objective/main point is not to prove that neutrinos have mass, but rather to show how this discovery ties to a bigger problem.

Sajjad1994 · Answer

Explanation

3. Based on the passage, the author most likely holds which one of the following views?

Explanation

The words  “most likely”  signal an inference question. You must have a good handle on the points of view presented in the passage to answer most inference questions; they will ask you which answer choice accords with a particular point of view.

Predicting an answer to this inference question is difficult. We are asked to find the answer choice with which the author would most likely agree, so our research will entail checking each answer choice against the passage as a whole.

(A)  is a distortion. Line 9 says that non-observable makes up 90% of the universe.

(B)  doesn’t fit the tone of the passage. The author has a positive tone in the final paragraph which doesn’t match the word  “incapable” . In addition, the author does not dispute the validity of the theory of gravitation as the universe-binding force.

(C) —the author says that neutrinos have a range of possible mass, and doesn’t dwell on the importance of pinning down that mass exactly.

(D) —the author says that gravitation is believed to shape the structure of the universe, and the rest of the passage discusses how we can explain gravity. There is no reason to think the author would think a force other than gravity is necessary to explain the universe. Thus  (D)  accords with the passage and is correct.

(E)  says that neutrinos make up most of the missing matter in the world, whereas the author says that neutrinos can make up at most 20% of the missing matter in the world.

Answer: D

5. The author’s attitude toward oscillation can most accurately be characterized as being

Explanation

You can quickly eliminate wrong answer choices in Author’s Attitude questions by eliminating answer choices that don’t fit the overall tone of the passage.

The author mentions oscillation in paragraph three, when discussing how we know that neutrinos have mass. The author takes the evidence for oscillation as proof that neutrinos have some slight mass, and he spends the following paragraph discussing the implications of that mass.  Choice (A)  matches well.

(B)  is a distortion. The author only mentions other forms of dark matter in a very oblique fashion at the end of the passage, and he certainly never ties oscillation to anything other than neutrinos.

(C) —the fraction of dark matter that is made up by neutrinos is addressed in paragraph four. The author never discusses misinterpretation at all, much less specifically in connection to oscillation.

(D)  says that the author feels skeptical towards oscillation. The author’s description, however, is a very cut-and-dry explanation of the experiment and why it shows that neutrinos have mass. Skepticism does not enter the picture.

(E) —the author never draws a distinction between things that can only occur in an experimental setting and those that occur in the real world. Thus  (E)  is out of scope.

Anwer: A

sting8 · Answer

Sajjad1994

"Neutrinos, which come in three types, are by far the
(25) most numerous kind of particle in the universe;"

Doesn't this imply option (A) from Q7 ?

bM22 · Answer

Hi  sting8 ,

I think this option is a trap answer. If you look at what is mentioned : Neutrinos, which come in three types,  are by far the
(25) most numerous kind of particle in the universe ;", but what's mentioned in the option is There are  more neutrinos in the universe than there are non-neutrinos . Non neutrinos imply all the particles in the universe except Neutrinos and we can't infer if there are more neutrinos in the universe when compared to the number of the rest of the particles.

Hope This Helps.
Thanks.

Sajjad1994 · Answer

The author says that neutrinos are the most abundant kind of particle in the universe. He never says, however, that they outnumber every other particle, as choice  (A)  says. Thus,  (A)  is never mentioned.

Sajjad1994 · Answer

Explanation

4. As described in the last paragraph of the passage, the cosmologists’ approach to solving the dark matter problem is most analogous to which one of the following?

Explanation

We have to find an answer choice that parallels the cosmologists’ approach as described in the final paragraph. Let’s start by abstracting their approach and then find the answer choice that matches best. The cosmologists are trying to solve a particular problem (where’s the missing matter?) and they have something (dark matter) which provides a partial solution (neutrinos) and which they hope to continue their efforts along the same lines (other elementary particles) to achieve a total solution (hold the universe together).

(A) is not parallel.  The child going to a chess book involves appealing to some informative authority who will answer all of the child’s questions.

(B) is not parallel.  The child has a partial solution (part of the money towards a bike) but instead of continuing his work, he changes his goal (the skateboard).

(C) is not parallel.  The child wants a particular solution (getting a dog) and receives something less than the expected (a cat), but changes the goal (loves the cat) rather than continuing towards the same goal.

(D) is parallel.   The child tries to solve a particular problem (go to a movie) and he has something (begging from siblings) which provides a partial solution (so me money from one sibling) and he hopes to continue his efforts along the same lines (begging from remaining siblings) to achieve a total solution (go to a movie).

(E) is not parallel.  The stated goal (playing sports) cannot be achieved until another, completely unrelated activity (homework) is carried out.

Answer: D

Sajjad1994 · Answer

Explanation

1. Which one of the following most accurately expresses the main idea of the passage?

Explanation

Accurately pre-phrasing the Purpose and Main Idea of the passage before you move on to the questions will turn into points on Test Day when you quickly and easily deal with Global questions. The author’s main idea centers around the role played by neutrinos in dark matter, as we saw during our critical reading.  (C)  captures both of these ideas.

(A)  is an excellent summary of the first paragraph, but it misses the point of the passage as a whole.

(B)  is a distortion. The passage says that although neutrinos make up no more than 20% of the missing mass in the universe, they are good start.  (B)  has a negative tone that does not match the passage.

(D)  is a detail from paragraph three, and thus incorrect.

(E)  is a 180. The passage takes the proof that neutrinos have mass as support for the idea that neutrinos compose dark matter.

Answer: C

Sajjad1994 · Answer

Explanation

2. Which one of the following titles most completely and accurately expresses the contents of the passage?

Explanation

A question that asks for a hypothetical title to the passage will include exactly the same ideas as the correct answer to a  “main idea”  or  “primary purpose”  question.

The author discusses dark matter in the first paragraph, neutrinos in the second, and neutrinos as dark matter in the remaining two. (B) brings together all of these ideas and captures the scope of the passage well.

(A) —the author never offers arguments against the existence of dark matter.

(C)  is a 180. The authors says the neutrinos are a good candidate for dark matter.

(D)  focuses on the first paragraph, and misses the passage’s scope by leaving out neutrinos.

(E)  is a detail from the third paragraph and misses the passage’s scope by leaving out the context in which neutrinos are discussed: dark matter.

Answer: B

gullyboy09 · Answer

Hi  Sajjad1994   GMATNinja

In option D, for the first half " A child seeking money to attend a movie is given some of the money by one of his siblings  " - it is analogous to the part that neutrino is a partial solution but passage stops there. But now in option D later part " and so decides to go to each of his other siblings to ask for additional money. " this is like a one more step forward (or what's next he's doing), but passage has not discussed what next step can be taken. Option D is best out of all, but I am not able to see the later part discussed.

guddo · Answer

4. As described in the last paragraph of the passage, the cosmologists’ approach to solving the dark matter problem is most analogous to which one of the following?

Cosmologists think most of the universe’s mass is “missing,” so they propose dark matter. New evidence suggests neutrinos have some mass and could explain about 20 percent of the missing mass, not all of it, but still enough to significantly improve our picture of what holds the universe together.

(A) A child seeking information about how to play chess consults a family member and so learns of a book that will instruct her in the game.

This is about finding a source of instructions. The cosmologists are not “learning where to find” an answer, they are using new evidence to explain part of the problem. Not a match.

(B) A child seeking to earn money by delivering papers is unable to earn enough money for a bicycle and so decides to buy a skateboard instead.

This is switching goals because the original goal is unattainable. The cosmologists are not abandoning the dark matter problem, they are treating neutrinos as a  partial solution  within it. Not a match.

(C) A child hoping to get a dog for his birthday is initially disappointed when his parents bring home a cat but eventually learns to love the animal.

This is accepting a substitute outcome emotionally. The passage is about refining an explanation with evidence, not learning to love an alternative. Not a match.

(D) A child seeking money to attend a movie is given some of the money by one of his siblings and so decides to go to each of his other siblings to ask for additional money.

Key parallel:  they need a total amount, they get some of it from one place, then they would still need additional sources to cover the rest. That matches neutrinos explaining some missing mass while more is still needed.

(E) A child enjoys playing sports with the neighborhood children but her parents insist that she cannot participate until she has completed her household chores.

This is about being blocked by a condition. The cosmologists are not being prevented from investigating, they are updating a theory based on evidence. Not a match.

Answer: (D)

guddo · Answer

You’re right that the passage does not name the “next step.” The analogy point is looser: because neutrinos cover only about 20 percent, the cosmologists’ approach  implicitly  requires looking elsewhere for the remaining mass. Option D’s second clause is just making that implication concrete (get part from one source, then seek the rest from other sources), not claiming the passage explicitly described those sources. That is why  the “ask other siblings” part is an analogy for the remaining gap , even if the passage leaves the  details  unspecified.

kartickdey · Answer

Although I agree that it might be the best available option, still I think it is quite extreme because of the words like "complete solution"

kartickdey · Answer

in the last two lines of the second paragraph author is not talking about nutrinos, rather about the general requirement for gravitation. From that perspective I think this option does not fit well. Rather I think option D is much relevant although it is extreme to some extent because of the word "significantly"

Sajjad1994 · Answer

Hello gullyboy09

An analogy does not need to match every surface detail. It needs to match the reasoning structure and attitude toward the partial result, not the literal sequence of events.

Sajjad1994 · Answer

The passage does not claim that neutrinos will lead to a  complete solution , only that this is the best theoretical solution yet and adds to understanding, which is more modest.

The  “could someday be extended to a complete solution”  is speculative, but is it supported?

Passage says:

This is  “the best theoretical solution yet”

It  “may add to our understanding of the role elementary particles play in holding the universe together”

So, the author does not say it will definitely extend to a complete solution, but the tone is hopeful about improving understanding.

Sajjad1994 · Answer

Read the relevant  lines (28-30)  from the passsage:

Neutrinos ... have long been assumed to have no mass. If so, that would disqualify them as dark matter. Without mass, matter cannot exert gravitational force; without such force, it cannot induce other matter to cohere.

In the general statement  “without such force, it cannot induce other matter to cohere”

“such force” = gravitational force.

So:

No mass = no gravity = no ability to cause other matter to  “cohere”  (stick together gravitationally).

But in  cosmology  context, cohere means  hold together into galaxies/clusters,  which is exactly what dark matter does: it provides extra gravity to bind structures that would otherwise fly apart given observable matter’s insufficient gravity.

(D)  makes no sense:  “induce other matter to become significantly more massive” ? That’s not about gravity binding structures; it’s about increasing mass, which is unrelated.

According to the theory of gravitation, every particle of matter in

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According to the theory of gravitation, every particle of matter in

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