One of the foundations of scientific research is that an experimental

Question

LSAT September 2006, Passage #4: Riddled Basins of Attraction

Similar to the Maize passage, the first paragraph of this passage is fairly easy to understand (it discusses the replication of experimental results in fairly clear terms). Thereafter, the passage discusses “riddled basins of attraction” and fractals as an analogy of systems where replicating results can be impossible. Those portions of the passage lead most students to feel that the passage was impossible.

One of the foundations of scientific research is that an experimental result is credible only if it can be replicated—only if performing the experiment a second time leads to the same result. But physicists John Sommerer and Edward Ott have conceived of a physical system in which even the least change in the starting conditions—no matter how small, inadvertent, or undetectable—can alter results radically. The system is represented by a computer model of a mathematical equation describing the motion of a particle placed in a particular type of force field.

Sommerer and Ott based their system on an analogy with the phenomena known as riddled basins of attraction. If two bodies of water bound a large landmass and water is spilled somewhere on the land, the water will eventually make its way to one or the other body of water, its destination depending on such factors as where the water is spilled and the geographic features that shape the water’s path and velocity. The basin of attraction for a body of water is the area of land that, whenever water is spilled on it, always directs the spilled water to that body.

In some geographical formations it is sometimes impossible to predict, not only the exact destination of the spilled water, but even which body of water it will end up in. This is because the boundary between one basin of attraction and another is riddled with fractal properties; in other words, the boundary is permeated by an extraordinarily high number of physical irregularities such as notches or zigzags. Along such a boundary, the only way to determine where spilled water will flow at any given point is actually to spill it and observe its motion; spilling the water at any immediately adjacent point could give the water an entirely different path, velocity, or destination.

In the system posited by the two physicists, this boundary expands to include the whole system: i.e., the entire force field is riddled with fractal properties, and it is impossible to predict even the general destination of the particle given its starting point. Sommerer and Ott make a distinction between this type of uncertainty and that known as “chaos”; under chaos, a particle’s general destination would be predictable but its path and exact destination would not.

There are presumably other such systems because the equation the physicists used to construct the computer model was literally the first one they attempted, and the likelihood that they chose the only equation that would lead to an unstable system is small. If other such systems do exist,  metaphorical examples of riddled basins of attraction  may abound in the failed attempts of scientists to replicate previous experimental results—in which case, scientists would be forced to question one of the basic principles that guide their work.   1 
 B 
 1) Which one of the following most accurately expresses the main point of the passage?

(A) Sommerer and Ott’s model suggests that many of the fundamental experimental results of science are unreliable because they are contaminated by riddled basins of attraction. 
(B) Sommerer and Ott’s model suggests that scientists who fail to replicate experimental results might be working within physical systems that make replication virtually impossible. 
(C) Sommerer and Ott’s model suggests that experimental results can never be truly replicated because the starting conditions of an experiment can never be re-created exactly. 
(D) Sommerer and Ott’s model suggests that most of the physical systems studied by scientists are in fact metaphorical examples of riddled basins of attraction. 
(E) Sommerer and Ott’s model suggests that an experimental result should not be treated as credible unless that result can be replicated.

2 
 D 
 2) The discussion of the chaos of physical systems is intended to perform which one of the following functions in the passage?

(A) emphasize the extraordinarily large number of physical irregularities in a riddled basin of attraction 
(B) emphasize the unusual types of physical irregularities found in Sommerer and Ott’s model 
(C) emphasize the large percentage of a riddled basin of attraction that exhibits unpredictability 
(D) emphasize the degree of unpredictability in Sommerer and Ott’s model 
(E) emphasize the number of fractal properties in a riddled basin of attraction

3 
 C 
 3) Given the information in the passage, Sommerer and Ott are most likely to agree with which one of the following?

(A) It is sometimes impossible to determine whether a particular region exhibits fractal properties. 
(B) It is sometimes impossible to predict even the general destination of a particle placed in a chaotic system. 
(C) It is sometimes impossible to re-create exactly the starting conditions of an experiment. 
(D) It is usually possible to predict the exact path water will travel if it is spilled at a point not on the boundary between two basins of attraction. 
(E) It is usually possible to determine the path by which a particle traveled given information about where it was placed and its eventual destination.

4 
 E 
 4) Which one of the following most accurately describes the author’s attitude toward the work of Sommerer and Ott?

(A) skeptical of the possibility that numerous unstable systems exist but confident that the existence of numerous unstable systems would call into question one of the foundations of science 
(B) convinced of the existence of numerous unstable systems and unsure if the existence of numerous unstable systems calls into question one of the foundations of science 
(C) convinced of the existence of numerous unstable systems and confident that the existence of numerous unstable systems calls into question one of the foundations of science 
(D) persuaded of the possibility that numerous unstable systems exist and unsure if the existence of numerous unstable systems would call into question one of the foundations of science 
(E) persuaded of the possibility that numerous unstable systems exist and confident that the existence of numerous unstable systems would call into question one of the foundations of science

5 
 C 
 5) According to the passage, Sommerer and Ott’s model differs from a riddled basin of attraction in which one of the following ways?

(A) In the model, the behavior of a particle placed at any point in the system is chaotic; in a riddled basin of attraction, only water spilled at some of the points behaves chaotically. 
(B) In a riddled basin of attraction, the behavior of water spilled at any point is chaotic; in the model, only particles placed at some of the points in the system behave chaotically. 
(C) In the model, it is impossible to predict the destination of a particle placed at any point in the system; in a riddled basin of attraction, only some points are such that it is impossible to predict the destination of water spilled at each of those points. 
(D) In a riddled basin of attraction, water spilled at two adjacent points always makes its way to the same destination; in the model, it is possible for particles placed at two adjacent points to travel to different destinations. 
(E) In the model, two particles placed successively at a given point always travel to the same destination; in a riddled basin of attraction, water spilled at the same point on different occasions may make its way to different destinations.

6 
 D 
 6) Which one of the following best defines the term “ basin of attraction ,” as that term is used in the passage?

(A) the set of all points on an area of land for which it is possible to predict the destination, but not the path, of water spilled at that point 
(B) the set of all points on an area of land for which it is possible to predict both the destination and the path of water spilled at that point 
(C) the set of all points on an area of land that are free from physical irregularities such as notches and zigzags 
(D) the set of all points on an area of land for which water spilled at each point will travel to a particular body of water 
(E) the set of all points on an area of land for which water spilled at each point will travel to the same exact destination

7 
 B 
 7) Which one of the following is most clearly one of the “ metaphorical examples of riddled basins of attraction ” mentioned in lines 52–53?

(A) A scientist is unable to determine if mixing certain chemicals will result in a particular chemical reaction because the reaction cannot be consistently reproduced since sometimes the reaction occurs and other times it does not despite starting conditions that are in fact exactly the same in each experiment. 
(B) A scientist is unable to determine if mixing certain chemicals will result in a particular chemical reaction because the reaction cannot be consistently reproduced since it is impossible to bring about starting conditions that are in fact exactly the same in each experiment. 
(C) A scientist is unable to determine if mixing certain chemicals will result in a particular chemical reaction because the reaction cannot be consistently reproduced since it is impossible to produce starting conditions that are even approximately the same from one experiment to the next. 
(D) A scientist is able to determine that mixing certain chemicals results in a particular chemical reaction because it is possible to consistently reproduce the reaction even though the starting conditions vary significantly from one experiment to the next. 
(E) A scientist is able to determine that mixing certain chemicals results in a particular chemical reaction because it is possible to consistently reproduce the reaction despite the fact that the amount of time it takes for the reaction to occur varies significantly depending on the starting conditions of the experiment.

Source:   LSAT Official PrepTest 50   
 Difficulty Level:   750

shoutout to:
 stonecold 
 warriorguy 
 abhimahna 
 gmatexam439  
 duahsolo 
 Vyshak

Guys try this passage.

auradediligodo · Accepted Answer

Hi everyone,
Got 5/7 correct here.

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P1

paragraph ones tells us that the scientific community normally relies on a general belief according to which the results of an experiment must be replicated in order to confirm the validity of the results.
However two scientists suggest that even the slightest chance in the initial condition of an experiment might lead to different results. The 2 scientists conceived a computer model based on an equation and in such model particles are subjected to force fields.

Brief summary : Two scientists shake the validity of a general belief in the scientific community

P2

The 2 scientists conceived their model on a similarity with the RBOA. Such system consists of 2 bodies of water and a landmass in between. Whenever the water is spilled on the landmass, such water will go to either one body or the other, and such movements will depend on different variables. Also, we are given that a basin of attraction is a land where, whenever water is spilled on it, will always direct the water to the same body.

Brief summary:  RBOA

P3

In paragraph 3 we are given that there are some areas in which it is not possible to forecast where the spilled water will go. Such areas are at the boundary between one basin of attraction and another. These areas are permeated by riddled fractals, that is irregularities such as zigzags etc... The only possible way to determine where the spilled water will go is to spill water in a location and see where it goes next. But if the water is spilled somewhere else (even if very close), the water could take a total different direction than the previous one.

Brief summary:  Impossibility of forecast directions

P4

Paragraph one applies the RBOA to their system. In such system the boundaries permeated with fractals are all over the system, making it impossible to forecast anything. In addition we know that differently from in this system, i a chaotic system we would be able to forecast at least the destination but not the path.

Brief summary:  Riddled fractals in the two scientists' system

P5

Paragraph 5 suggests that the system created by the 2 scientists might be one of the many that could be created. In addition, if many such systems were to exist, the riddled basin of attraction might explain lots of failed experiments, leading scientists to review their general belief.

Main point

The main point is to discuss the system created by 2 scientists in order to suggest that the scientific community might need to rediscuss one of its general belief

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1) Which one of the following most accurately expresses the main point of the passage?

Pre-thinking

Main point question

Refer to main point above

(A) Sommerer and Ott’s model suggests that many of the fundamental experimental results of science are unreliable because they are contaminated by riddled basins of attraction. 
 This choice fails to address the right portion of experimental results. In fact the two scientists try to address those experimental results which cannot be replicated while this option addresses all kind of experimental results

(B)   Sommerer and Ott’s model suggests that scientists who fail to replicate experimental results might be working within physical systems that make replication virtually impossible. 
 In line with pre-thinking

(C) Sommerer and Ott’s model suggests that experimental results can never be truly replicated because the starting conditions of an experiment  can never be re-created exactly.  
 too extreme and not the reason

(D) Sommerer and Ott’s model suggests that   most   of the physical systems studied by scientists are in fact metaphorical examples of riddled basins of attraction. 
 Most is quite a strong word; what the two scientists try to address are those experiments that cannot be replicated but we don't know whether such experiments represent most of the total experiments

(E) Sommerer and Ott’s model suggests that an experimental result should not be treated as credible unless that result can be replicated.
 Opposite

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2) The discussion of the chaos of physical systems is intended to perform which one of the following functions in the passage?

Pre-thinking

Function question

The discussion at hand is presented in P4. Here we can see that the 2 scientists make a distinction between their system and a chaotic system, suggesting that their system is even worse than a chaotic system when it comes to forecast a direction, destination etc.....

(A) emphasize the extraordinarily large  number  of physical irregularities in a riddled basin of attraction 
 not the purpose

(B) emphasize the  unusual types  of physical irregularities found in Sommerer and Ott’s model 
 not the purpose

(C) emphasize the large  percentage  of a riddled basin of attraction that exhibits unpredictability 
 not the purpose

(D)   emphasize the degree of unpredictability in Sommerer and Ott’s model 
 In line with pre-thinking

(E) emphasize the  number  of fractal properties in a riddled basin of attraction
 not the purpose

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3) Given the information in the passage, Sommerer and Ott are most likely to agree with which one of the following?

Pre-thinking

Inference question

Let's analyze each option

(A) It is sometimes impossible to determine whether a particular region exhibits fractal properties. 
 Whether a region exhibits or not fractal properties is not discussed

(B) It is sometimes impossible to predict even the general destination of a particle placed in a chaotic system. 
 This topic is discussed in P4 and the 2 scientists claim that it is generally possible to predict such.

(C)   It is sometimes impossible to re-create exactly the starting conditions of an experiment. 
 The all system created by the 2 scientists is based on the reasoning according to which lots of failed replication hav to do with riddled basin of attractions. Now riddled basin of attractions are permeated by fractal properties and in such scenarios even the slightest change in the initial conditions may change drastically the results. Hence we can infer that lots of failed replication are related to the impossibility of re-creating the initial conditions

(D) It is usually possible to predict the exact path water will travel if it is spilled at a point not on the boundary between two basins of attraction. 
 The prediction of the path is not discussed in the passage and hence we cannot make inferences about it

(E) It is usually possible to determine the path by which a particle traveled given information about where it was placed and its eventual destination. 
 The prediction of the path is not discussed in the passage and hence we cannot make inferences about it

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4) Which one of the following most accurately describes the author’s attitude toward the work of Sommerer and Ott?

Pre-thinking

Author's attitude question

The author seems intrigued by the implications of the system created by the 2 scientists. We can identify her attitude from this lines in the last paragraph: "   and the likelihood that they chose the only equation that would lead to an unstable system is small.  "

(A)   skeptical   of the possibility that numerous unstable systems exist but confident that the existence of numerous unstable systems would call into question one of the foundations of science 
 Not skeptikal

(B)   convinced   of the existence of numerous unstable systems and   unsure   if the existence of numerous unstable systems calls into question one of the foundations of science 
 The author is not unsure

(C)   convinced   of the existence of numerous unstable systems and   confident   that the existence of numerous unstable systems calls into question one of the foundations of science 
 Convinced seems a strong word to use

(D)   persuaded   of the possibility that numerous unstable systems exist and   unsure   if the existence of numerous unstable systems would call into question one of the foundations of science 
 The author is not unsure

(E)     persuaded   of the possibility that numerous unstable systems exist and   confident   that the existence of numerous unstable systems would call into question one of the foundations of science
 Persuaded fits more than convinced, hence correct

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5) According to the passage, Sommerer and Ott’s model differs from a riddled basin of attraction in which one of the following ways?

Pre-thinking

Detail question

Their model is completely permeated by riddled basins of attractions

(A) In the model, the behavior of a particle placed at any point in the system is chaotic; in a riddled basin of attraction, only water spilled at some of the points behaves chaotically. 
 The behavior is not chaotic

(B) In a riddled basin of attraction, the behavior of water spilled at any point is chaotic; in the model, only particles placed at some of the points in the system behave chaotically. 
 no chaos

(C)   In the model, it is impossible to predict the destination of a particle placed at any point in the system; in a riddled basin of attraction, only some points are such that it is impossible to predict the destination of water spilled at each of those points. 
 Yes, in the model it is never possible to forecast directions while in the riddled basin the problem is related only to the boundaries

(D) In a riddled basin of attraction, water spilled at two adjacent points always makes its way to the same destination; in the model, it is possible for particles placed at two adjacent points to travel to different destinations. 
 completely wrong

(E) In the model, two particles placed successively at a given point always travel to the same destination; in a riddled basin of attraction, water spilled at the same point on different occasions may make its way to different destinations.
 incorrect

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6) Which one of the following best defines the term “basin of attraction,” as that term is used in the passage?

Pre-thinking

Detail question

From P2:" The basin of attraction for a body of water is the area of land that, whenever water is spilled on it, always directs the spilled water to that body. 
 "

(A) the set of all points on an area of land for which it is possible to predict the destination, but not the path, of water spilled at that point 
 The body of water is neglected in this option

(B) the set of all points on an area of land for which it is possible to predict both the destination and the path of water spilled at that point 
 The body of water is neglected in this option

(C) the set of all points on an area of land that are free from physical irregularities such as notches and zigzags 
 The body of water is neglected in this option

(D)   the set of all points on an area of land for which water spilled at each point will travel to a particular body of water 
 In line with pre-thinking

(E) the set of all points on an area of land for which water spilled at each point will travel to the same exact destination
 The body of water is neglected in this option

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7) Which one of the following is most clearly one of the “metaphorical examples of riddled basins of attraction” mentioned in lines 52–53?

Pre-thinking

Analogous statement question

We need to have in mind the system of the two scientists: such system is completely permeated with fractals properties and even a slight change in the initial conditions leads to a drastic change in the results

(A) A scientist is unable to determine if mixing certain chemicals will result in a particular chemical reaction because the reaction cannot be consistently reproduced since sometimes the reaction occurs and other times it does not despite starting conditions that are in fact exactly the same in each experiment. 
 If the initial conditions were exactly the same in the system created by the two scientists, the results would be the same. out

(B)   A scientist is unable to determine if mixing certain chemicals will result in a particular chemical reaction because the reaction cannot be consistently reproduced since it is impossible to bring about starting conditions that are in fact exactly the same in each experiment. 
 In line with pre-thinking

(C) A scientist is unable to determine if mixing certain chemicals will result in a particular chemical reaction because the reaction cannot be consistently reproduced since it is impossible to produce starting conditions that are even approximately the same from one experiment to the next. 
 The goal is to have the same starting conditions, not the approximate starting conditions since already in the latter case the results would be different

(D) A scientist is able to determine that mixing certain chemicals results in a particular chemical reaction because it is possible to consistently reproduce the reaction even though the starting conditions vary significantly from one experiment to the next. 
 out of scope

(E) A scientist is able to determine that mixing certain chemicals results in a particular chemical reaction because it is possible to consistently reproduce the reaction despite the fact that the amount of time it takes for the reaction to occur varies significantly depending on the starting conditions of the experiment.
 out of scope

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It is a good day to be alive!

PranavSomani · Answer

Can someone pls explain that how is the 3rd question "C" and not "D" ?

shailabh · Answer

PranavSomani

If you read carefully, the third para clearly clearly addresses this issue. While one may be slightly confused with the 1st half of third para, but this line (" Along such a boundary, the only way to determine where spilled water will flow at any given point is actually to spill it and observe its motion ") makes it amply clear that author does not believe that it is  usually possible  to  predict  the exact path water will travel. Hence, D is out.

Wrt C, para 4 addresses it to a great extent, and para 5 makes it very clear.

stne · Answer

What you have answered to PranavSomani is applicable only when the water is dropped in the boundary between two basins of attraction. Well as option D clearly states that water is NOT dropped on the boundary between two basins of attraction.

The reason option D is wrong is because even if water is NOT dropped on the boundary between two basins of attraction , rather water is dropped on one basin of attraction then the destination is predictable NOT the exact path. The destination is the body of water into which the drop of water will finally land.
No where in the passage does it state that dropping water anywhere on the basin of attraction will always have the same EXACT PATH to the relevant water body.

Which water body water will go is predictable NOT the exact path. But when water is dropped in the boundary and NOT on any particular basin of attraction then nothing is predictable .

Hence option C is correct.

Hope it helps.

hero_with_1000_faces · Answer

Paragraph 1:

Looks like a hard science passage. We need to be clear on what the central concept is/key definitions. We also need to understand the viewpoints of people mentioned in the passage as well as the author's opinion.

(Tone) Looks like the passage is going to be descriptive rather than polemical. We're discussing the work of Sommerer and Ott.

(MP) They made a computer model that has some implications for the scientific method.

Paragraph 2:

(MP/View) Discusses S & O's work by analogy with "riddled basins of attraction" ¶ 2 largely discusses this analogy.

Paragraph 3:

(MP/View) Continuation of discussion of "riddled basin" analogy. We should note that we will likely be asked about details from these two paragraphs. Do not go overboard with memorizing the whole thing. Just note that this is important, detailed information.

Paragraph 4:

(MP/View) Still in S&O's viewpoint. Now discussing contrast between their work and what they call "chaos." Notice that the definition of this term in quotes will likely be important, i.e. you'll have to come back to it later.

Paragraph 5:

(MP/View) Now we're in author's viewpoint. Further, the author makes an (Argument) that other systems like that of S & O likely exist. Author ratiocinates based on probability. This paragraph confirms that the author is largely in agreement with the observations of S & O and views their work as significant.

Overall Main Point would be something along the lines of:

Passage about the work of S & O, which suggests that difficulty replicating scientific results may have to do with unrepeatable initial conditions. This work may have further implications.

Notice we're trying to work from general to specific as always. We'll have plenty of opportunities to dig into the minutiae of this passage while we are answering questions.

hero_with_1000_faces · Answer

Question 1

it seems most people were torn between B and C, so here we g:

Answer choice (B) discusses what happens when scientists fail to replicate experiments. If a scientist fails to replicate a result, this failure might be due to this "riddled basin of attraction" metaphor/phenomenon.
Answer choice (C) makes a much stronger statement, that experimental results in general cannot be replicated because of this riddled basin of attraction phenomenon.

In other words, (B) limits itself to situations in which replication has been unsuccessful. (C) makes a broader, more extreme claim. This difference in degree provides a good tool for contrasting these two answer choices and determining which one is better supported by the text. In this case, we can find evidence in lines 54 to the end of the passage (which is where the author states the thesis): when scientists fail to replicate experiments, it might be because of this principle illustrated in the riddled basins of attraction.

This statement is a pretty good match for answer choice (B). Answer choice (C) goes beyond what the text supports and is too extreme/out of scope.

hero_with_1000_faces · Answer

Question 2
Answer is D

Here we are asked to define a conceptual reference that is sprinkled throughout the passage, but becomes much clearer once the uncertainty concept of "chaos" is introduced to the reader. Note how with the riddled basins of attraction, even general destination becomes impossible to predict. This concept of predicting general destination is then carried over to distinguish it from the uncertainty principle of chaos as it's used in particle physics and the prediction of the path of a particle. In other words with particle physics, "chaos" is something less chaotic than the study of the riddled basins of attraction issue because at least the general destination of the particle can be predicted whereas the water pathway's general destination cannot be predicted at all.

anothermillenial · Answer

P1. Repeated results makes science research credible. BUT JS and EO system: small change > extreme/radical results with model.

P2. JS & EO system foundation on riddled basin of attraction. Defined: land area that always pulls water to that one body of water.

P3. Reasons the basis of attraction is hard to predict: fractal properties. Only known via observation/trial + error.

P4. JS & EO use basin to describe force field and particle destination as “uncertainty” and “chaos” - general direction known only, not specific path.

P5. Probably other systems like this meaning failure in science is questionable… (since it’s probable that experimental foundation of science may be flawed!! failures are like fractals that when replicated will definitely go elsewhere).

1) Which one of the following most accurately expresses the main point of the passage?

Main Idea: Science research principle of experimenting to replication may need to be re-evaluated because systems described by JS & EO prove systems are generally unstable. Implies difficulty of achieving same result endlessly.

(A) Sommerer and Ott’s model suggests that  many of the fundamental experimental results  of science are unreliable because they are contaminated by riddled basins of attraction. 
( B) Sommerer and Ott’s model suggests that scientists who fail to replicate experimental results might be working within physical systems that make replication virtually impossible .  
(C) Sommerer and Ott’s model suggests that experimental results  can never be truly replicated  because the starting conditions of an experiment can never be re-created exactly.  
(D) Sommerer and Ott’s model suggests that most of the physical systems studied by scientists  are in fact metaphorical examples of riddled basins of  attraction.  
(E) Sommerer and Ott’s model suggests that an experimental  result should not be treated as credible  unless that result can be replicated.

2) The discussion of the chaos of physical systems is intended to perform which one of the following functions in the passage?

This is a detail question. “Chaos” shows up in P4 of the passage and distinguished from the idea of uncertainty. It is supposed to be different from complete uncertainty, which says “it is impossible to predict even the general destination of the particle given its starting point”.

(A) emphasize the  extraordinarily large number  of physical irregularities in a riddled basin of attraction  
(B) emphasize the  unusual types of physical irregularities  found in Sommerer and Ott’s model  
(C) emphasize the  large percentage  of a riddled basin of attraction that exhibits unpredictability  
(D) emphasize  the degree of unpredictability in Sommerer and Ott’s model   
(E) emphasize  the number of fractal properties in a riddled basin of attraction

3) Given the information in the passage, Sommerer and Ott are most likely to agree with which one of the following?  
This is an inference question. So we’re looking for S & O’s opinion about how systems are made unstable with different starting points.

(A) It is sometimes impossible to determine whether  a particular region exhibits fractal properties .  
(B) It is  sometimes impossible to predict even the general destination of a particle  placed in a chaotic system.  
 (C) It is sometimes impossible to re-create exactly the starting conditions of an experiment.   
(D) It is usually possible to predict  the exact path water  will travel if it is spilled at a point not on the boundary between two basins of attraction.  
(E) It is usually possible to  determine the path by which a particle traveled given information about where it was placed and its eventual destination .

4) Which one of the following most accurately describes the author’s attitude toward the work of Sommerer and Ott?  
This is specifically asking about the AUTHOR’s attitude. He seems to be pretty “meH” about it. This passage is a little more exploratory, though edging on “yes, if this is right than the whole field of science needs questioning.”

(A)  skeptical  of the possibility that numerous unstable systems exist but confident that the existence of numerous unstable systems would call into question one of the foundations of science  
(B)  convinced  of the existence of numerous unstable systems and unsure if the existence of numerous unstable systems calls into question one of the foundations of science  
(C)  convinced  of the existence of numerous unstable systems and confident that the existence of numerous unstable systems calls into question one of the foundations of science  
(D) persuaded of the possibility that numerous unstable systems exist and  unsure if the existence of  numerous unstable systems would call into question one of the foundations of science  
 (E) persuaded of the possibility that numerous unstable systems exist and confident that the existence of numerous unstable systems would call into question one of the foundations of science

5) According to the passage, Sommerer and Ott’s model differs from a riddled basin of attraction in which one of the following ways?  
Specific detail takes us back to P2-P4. Their model is different because the basis of attraction has impossibilities only at the BOUNDARY. Their mathematical analogy is the basis of attraction but “riddled entirely” because it takes the whole force field as a boundary of unpredictability.

(A) In the model, the behavior of  a particle placed at any point in the system is chaotic;  in a riddled basin of attraction, only water spilled at some of t he points behaves chaotically .  
(B) In a riddled basin of attraction, the behavior of water spilled at any point is chaotic; in the model, only particles placed at some of the points in the system  behave chaotically .  
 (C) In the model, it is impossible to predict the destination of a particle placed at any point in the system; in a riddled basin of attraction, only some points are such that it is impossible to predict the destination of water spilled at each of those points.   
(D) In a riddled basin of attraction, water spilled at two adjacent points always makes its way to the same destination; in the model,  it is possible for particles placed at two adjacent points to travel to different destinations .  at a given point always travel to the same destination ; in a riddled basin of attraction, water spilled at the same point on different occasions may make its way to different destinations.

6) Which one of the following best defines the term “basin of attraction,” as that term is used in the passage?  
A detail question. Used mainly as an analogy/phenomena of the destination of a water/change/impact to a system. P2 says: “The basin of attraction for a body of water is the area of land that, whenever water is spilled on it, always directs the spilled water to that body.”

(A) the set of all points on an area of land for which  it is possible to predict the destination, but not the path,  of water spilled at that point  
(B) the set of all points on an area of land for which it is possible to predict both the destination and  the path of water  spilled at that point  
(C) the set of all points on an area of land  that are free from physical irregularities such as notches and zigzags   
(D) the set of all points on an area of land for which water spilled at each point will travel to a particular body of water   
 (E) the set of all points on an area of land for which water spilled at each point  will travel to the same exact destination

7) Which one of the following is most clearly one of the “metaphorical examples of riddled basins of attraction” mentioned in lines 52–53?  
The most clear “metaphorical example” would be one that is unpredictable at almost all areas, not just at a boundary between two basins. So an answer choice that shows that when something’s destination is completely unknown even if you know how it started at the given point.

(A) A scientist is unable to determine if mixing certain chemicals will result in a particular chemical reaction because the reaction cannot be consistently reproduced  since sometimes the reaction occurs and other times it does not  despite starting conditions that  are in fact exactly the same  in each experiment.  
(B) A scientist is unable to determine if mixing certain chemicals will result in a particular chemical reaction because the reaction cannot be consistently reproduced since  it is impossible to bring about starting conditions that are in fact exactly the same in each experiment.    
(C) A scientist is unable to determine if mixing certain chemicals will result in a particular chemical reaction because the reaction cannot be consistently reproduced since it is impossible to produce starting conditions  that are even approximately the same  from one experiment to the next. 
(D) A scientist  is able to determine that mixing certain chemicals results  in a particular chemical reaction because it is possible to consistently reproduce the reaction even though the starting conditions vary significantly from one experiment to the next.  
(E) A scientist  is able to determine that mixing certain chemicals results  in a particular chemical reaction because it is possible to consistently reproduce the reaction despite the fact t hat the amount of time it takes  for the reaction to occur varies significantly depending on the starting conditions of the experiment.

akt715 · Answer

How is D the correct answer for Q6 ? Can someone explain? the option mentions-- will travel to a  particular  body of water. But in third passage it is mentioned -In  some geographical formations  it is sometimes impossible to predict, not only the exact destination of the spilled water, but even which  body of water  it will end up in. So that's why I think A is better option.

Sajjad1994 · Answer

Explanation

6) Which one of the following best defines the term “basin of attraction,” as that term is used in the passage?

Difficulty Level:   700

Explanation

The author defines  “basin of attraction”  in  paragraph 2 , as  “the area of land that, whenever water is spilled on it, always directs the spilled water to  .”  That’s answer choice  (D).

None of the other answer choices captures that definition provided in the passage—they all bring in details that do not relate to the meaning of a basin of attraction.

Answer: D

mbaintern2025 · Answer

Would it be possible to post the OE for #3 and #7? I'm not sure where the support for these questions are.

Sajjad1994 · Answer

Explanation

3) Given the information in the passage, Sommerer and Ott are most likely to agree with which one of the following?

Difficulty Level:   700

Explanation

The author is not just interested in describing the model posited by Sommerer and Ott; he is interested in the implications of that model. According to the passage, the physicists’ model showed that there could be a system so unstable that valid experimental results could not be duplicated. Answer  choice (C)  identifies one possible way the system instability could manifest itself: an inability to recreate the starting conditions of an experiment.

(A)  In the passage, determining the existence of the fractal properties in Sommerer and Ott’s model was never an issue. The significance of fractal properties was that their existence created uncertainty in the behavior of a particle dropped into a riddled basin of attraction.

(B)  is a 180. The passage expressly states that in a chaotic system, the general destination of a particle can be predicted.

(D)  and  (E)  both go far beyond the scope of the passage. A basin of attraction is briefly defined, but the passage never states or suggests that one could usually predict the exact path water will travel if spilled at a point not on the boundary of two ordinary basins of attraction. Likewise, the author never discusses the possibility of determining the path by which a particle traveled, based upon its starting and ending points.

Answer: C

Sajjad1994 · Answer

Explanation

7) Which one of the following is most clearly one of the “metaphorical examples of riddled basins of attraction” mentioned in lines 52–53?

Difficulty Level:   700

Explanation

This question is made especially difficult because it comes at the end of a particularly difficult section, it is unusually long for a reading comprehension question, and each answer choice varies only subtly from the others. Stay calm and treat it just as you would any other reading comprehension question, however, and it becomes much more manageable. In  paragraph 5 , the metaphorical examples of riddled basins of attraction refer to models like the physicists’ model, models of unstable systems for which it is impossible to duplicate experimental conditions.

Doing a vertical scan to look for broad differences between the answer choices, we can eliminate  (D)  and  (E)  because they do not involve an inability to replicate experimental results.  (A)  fails because in the repetitions of the experiment, it is possible to exactly replicate the starting conditions of the experiment.

(B)  captures all of the uncertainties of Sommerer and Ott’s model—results cannot be duplicated because it is impossible to duplicate exactly the starting conditions of the experiment, so it’s our correct answer.

For the record,  (C)  fails because starting conditions that are approximately the same don’t correspond to Sommerer and Ott’s unstable system. As described in  paragraph 1 , in the physicists’ model, the tiniest, most inadvertent, imperceptible change in the starting conditions of the experiment would preclude replication of an experimental result.

Answer: B

RenB · Answer

HarshR9  Can you please help me clealy understand why 'persuaded' is better than 'convinced' here?
When I am presuming something, am I not convinced and thus presuming something to be true?
And 'persuaded' implies being persuaded by something or someone right? Can you help me understand this better in the given context?

HarshavardhanR · Answer

Hey RenB , Sure. Let me try to help! (thoroughly enjoyed solving this passage, btw!) Here is my understanding of this -> When we presume something, it means that we are assuming that thing to be the case, usually based on some strong evidence/high probability/etc. Even we, who are making the presumption, are not a 100% sure about that thing being the case. We are just assuming (presuming) that that thing should be the case, based on what we know. We are reasonably sure in our minds but not a 100% sure - which is why we use the word "presume". In other words, I believe there is a tiny (very tiny!) gap between presuming something and being a 100% certain or a 100% convinced about it. One way to think about this -> If you were already 100% convinced about something, you would not state that you presume that thing to be true. The use of "presumably" suggests that you find it safe to assume that thing to be true, but there is still an element of uncertainty, even as per you! Example: (1) A lethal bomb went off in the middle of a crowded market. There were at least 5000 people in the market at the time. At least 2000 people died. I (the author) know as a fact that at least 2000 people died. Hence, I am giving this as a fact. No need to presume. (2) A lethal bomb went off in the middle of a crowded market. There were at least 5000 people in the market at the time. I believe that at least 2000 people died. I (the author) am convinced (in my head) that at least 2000 people died. It may or may not be true, but I believe this to be true. Hence, I provide my opinion - what I am convinced about - at least 2000 people died. Again, because I am 100% convinced about this, I state my belief as is - no presumption (assumption). (3) A lethal bomb went off in the middle of a crowded market. There were at least 5000 people in the market at the time. It is safe to presume that at least 2000 people died. Based on the bomb's lethality and the fact that it went off in a crowded market which had 5000 people at the time of detonation, Clearly, I think there is a very high chance that at least 2000 people died. Hence, I say that it is safe to presume so. But notice that there is still a small element of uncertainty I am displaying here. In this passage -> - The equation these physicists came up with was literally the first one they even tried. ----> "So, who knows how many more such cases (where repeatability is impossible) will come out once people make more attempts?" - The probability that of all the possible equations they could have come up with, they came up with THE one equation that leads to an unstable system - small ----> "in other words, it is more likely that these physicists stumbled on one of possibly many many such equations that lead to an unstable system (and thus challenge the "repeatability is critical" notion science operates with)". Based on the above points, the author says - " thus, presumably , there are other such systems". The author finds the above argument to be persuasive enough to be reasonably confident -> to assume (presume) that there are other such systems. "Convinced" may be a bit too extreme. Hope this helps. When I solved this question, I had kept choice C ("convinced") on hold - it seemed reasonably decent at that moment. Then, when I saw choice E, I deliberated on both choices and reasoned out that choice E is more sensible. In the absence of choice E, I would have gone for choice C

. ___ Harsha Enthu about all things GMAT | Exploring the GMAT space | My website: gmatanchor.com

Raman109 · Answer

4) Which one of the following most accurately describes the author’s attitude toward the work of Sommerer and Ott?

(A) skeptical of the possibility that numerous unstable systems exist but confident that the existence of numerous unstable systems would call into question one of the foundations of science - skeptical is wrong.

(B) convinced of the existence of numerous unstable systems and unsure if the existence of numerous unstable systems calls into question one of the foundations of science - convinced is wrong, as the passage indicates the author is persuaded of the possibility, not fully convinced. Moreover, unsure is wrong as the passage says if such systems do exist, it would force scientists to question one of their basic principles

(C) convinced of the existence of numerous unstable systems and confident that the existence of numerous unstable systems calls into question one of the foundations of science - Wrong.

(D) persuaded of the possibility that numerous unstable systems exist and unsure if the existence of numerous unstable systems would call into question one of the foundations of science - persuaded is ok, but unsure is wrong.

(E) persuaded of the possibility that numerous unstable systems exist and confident that the existence of numerous unstable systems would call into question one of the foundations of science - ok

Raman109 · Answer

7) Which one of the following is most clearly one of the “metaphorical examples of riddled basins of attraction” mentioned in lines 52–53?

(A) A scientist is unable to determine if mixing certain chemicals will result in a particular chemical reaction because the reaction cannot be consistently reproduced since sometimes the reaction occurs and other times it does not despite starting conditions that are in fact exactly the same in each experiment. - No. This talks about the scenario where the starting conditions are the same.

(B) A scientist is unable to determine if mixing certain chemicals will result in a particular chemical reaction because the reaction cannot be consistently reproduced since it is impossible to bring about starting conditions that are in fact exactly the same in each experiment. - This is correct as "since it is impossible to bring about starting conditions that are in fact exactly the same in each experiment" aligns with what the passage would like to convey that it's very difficult to create the exact same conditions as even the minor change can provide drastic different results. "John Sommerer and Edward Ott have conceived of a physical system in which even the least change in the starting conditions—no matter how small, inadvertent, or undetectable—can alter results radically."

(C) A scientist is unable to determine if mixing certain chemicals will result in a particular chemical reaction because the reaction cannot be consistently reproduced since it is impossible to produce starting conditions that are even approximately the same from one experiment to the next. - No. "since it is impossible to produce starting conditions that are even approximately the same from one experiment to the next" means that the starting points are different every time, and as the starting points are different, the endpoints are different. Alternatively, "approximately the same" is an issue. Because "approximately the same" will not produce the same effect as the passage mentions even a minuscule change produces a different result. So the challenge is producing exactly the same conditions and not "approximately the same." Wrong.

On the contrary, the passage tries to say that we want to create the same conditions, but its virtually impossible to create as even the minor change can change the same.

(D) A scientist is able to determine that mixing certain chemicals results in a particular chemical reaction because it is possible to consistently reproduce the reaction even though the starting conditions vary significantly from one experiment to the next. - Wrong.

(E) A scientist is able to determine that mixing certain chemicals results in a particular chemical reaction because it is possible to consistently reproduce the reaction despite the fact that the amount of time it takes for the reaction to occur varies significantly depending on the starting conditions of the experiment. - "it is possible to consistently reproduce the reaction" is wrong and time is out of scope.

VerbalBot · Answer

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