That lunar craters are not distributed evenly over the lunar surface

Question

That lunar craters are not distributed evenly over the lunar surface is immediately obvious with even a small telescope. Craters also appear in a wide range of sizes from only a few meters across to hundreds of kilometers in diameter. The maria (the very large plains) are noticeably devoid of large craters. Any explanation of crater formation must clearly take these facts into account. There are two main theories concerning the origin of the lunar craters: one is that they were formed by the impact of meteorites, the other that they are due to some type of volcanic activity. According to the former theory, the large majority of the craters were formed during the early stages of the Moon's development when, as seems possible, the number of meteoritic bodies moving in orbits similar to that of the Earth-Moon system was quite large. Since the Moon, unlike the Earth, possesses no atmosphere, such bodies would reach the lunar surface at a higher velocity than they would reach Earth. They also would not be affected by frictional burning such as they would undergo when plunging through the terrestrial atmosphere. When a large body strikes the lunar surface, it is not stopped at the moment of impact but penetrates to a depth that depends on its mass, radius, and impact velocity.

If we are to explain the very large craters on the assumption that several meteorites fell close together (in space, although not necessarily in time), this would imply that such craters should have  uneven floors , not only indented to varying degrees by the several impacts but strewn with boulders and debris from the breakup of the meteorites themselves. Observation, however, suggests that the floors of large craters are smoother than can be accounted for by this theory unless there is some other mechanism whereby the floor becomes appreciably smoother following the impact.

One mechanism that has been suggested is that those meteorites that formed the craters fell on the lunar surface when the Moon was in a semi plastic condition or, if they fell after the lunar crust had solidified, that the impact itself would liquefy the surface rock sufficiently to force it to flow rather like lava. This liquefying of the rock at the moment of impact has also been put forward to explain the presence in some craters of a central mountain peak since we know, from high-speed photography of drops falling into liquids that a jet is formed in the center of an impact region.

There is unfortunately, one very serious objection to this idea. When a body the size and shape of a meteorite strikes solid rock it is quite probable that no intermediate liquid phase of the surface rock is ever produced.    1 
 1. According to the passage, one hypothesis proposed to explain the smoothness of the floors of large craters argues that the smoothness is a result of the

(A) disintegration of meteorites 
(B) liquefying of surface rock 
(C) numerous impact of meteorites 
(D) polar concentration of craters 
(E) frictional burning of matter

2 
 2. The purpose of the first paragraph is to

(A) summarize the evidence supporting a scientific theory 
(B) explain what is known about a scientific puzzle 
(C) introduce a theory that has been proved correct 
(D) describe phenomena to be explained 
(E) clarify the meaning of an obscure statement

3 
 3. The author fails to suggest any explanation for which of the following statements?

(A) There is little evidence of the breakup of meteorites on the floors of lunar craters. 
(B) Large numbers of meteorites struck the lunar surface during the Moon's formation. 
(C) Meteorites are likely to penetrate the lunar surface. 
(D) Some craters contain a central mountain peak. 
(E) The maria are devoid of large craters.

4 
 4. Which of the following statements about the meteorite-impact theory is most clearly supported by the information in the passage?

(A) It is more acceptable to scientists than is the volcanism theory. 
(B) It is able to explain some observed features of the Moon's surface. 
(C) It is one of several theories all of which seem equally tenable to scientists. 
(D) Its importance is primarily historical. 
(E) It has been abandoned by most scientists.

5 
 5. The passage states that, in contrast to meteorites that enter the Earth's atmosphere meteorites striking the Moon are

(A) likely to be almost entirely burned up 
(B) likely to fall close together 
(C) likely to liquefy immediately 
(D) able to create craters of widely varying diameters 
(E) able to hit the surface at greater speeds

6 
 6. The author suggests that the theory that has been presented to explain the existence of central mountain peaks in some craters is based on

(A) the author's own observation of the behavior of lunar rock
(B) inadequate evaluations of the material structure of-the lunar crust
(C) inference from an apparently similar situation
(D) conjectures with which the author agrees
(E) information that has become outdated

7 
 7. The author considers an explanation for the formation of very large lunar craters and then evaluates the explanation as

(A) confirmed by the characteristics of meteorites as they travel through space 
(B) supported by observations concerning the liquefying of rocks 
(C) incompatible, without further additions. with evidence of the smoothness of crater floors 
(D) improbable because of a disparity with the known causes of analogous formations on Earth 
(E) inconsistent if unmodified, with the facts about the distribution of the large lunar craters

8 
 8. It can be inferred from the passage that unevenness in the floors of craters ( Highlighted ) should have resulted from the fact that

(A) the meteorites that formed the craters had different masses or impact velocities 
(B) the meteorites that formed the craters were all traveling at the same speed 
(C) the meteorites that formed the craters all reached the Moon's surface at the same time 
(D) when the meteorites struck the Moon, its surface was in a semi plastic condition 
(E) when the meteorites struck the Moon, its surface was already uneven

Oppenheimer1945 · Answer

1. According to the passage, one hypothesis proposed to explain the smoothness of the floors of large craters argues that the smoothness is a result of the

(A) disintegration of meteorites 
 (B) liquefying of surface rock (True) 
(C) numerous impact of meteorites
(D) polar concentration of craters
(E) frictional burning of matter

One mechanism that has been suggested is that those meteorites that formed the craters fell on the lunar surface when the Moon was in a semi plastic condition or, if they fell after the lunar crust had solidified, that the impact itself would liquefy the surface rock sufficiently to force it to flow rather like lava.

2. The purpose of the first paragraph is to

(A) summarize the evidence supporting a scientific theory (there is no evidences. Author is stating theories)
(B) explain what is known about a scientific puzzle (author is not explaining something which is known)
(C) introduce a theory that has been proved correct (correctness of theory is not proven here)
 (D) describe phenomena to be explained (author introduces and describes the crater formation which he explains in upcoming paragraphs) 
(E) clarify the meaning of an obscure statement (nowhere the author is clarifying meaning of statement)

3. The author fails to suggest any explanation for which of the following statements?

(A) There is little evidence of the breakup of meteorites on the floors of lunar craters.
If we are to explain the very large craters on the assumption that several meteorites fell close together (in space, although not necessarily in time), this would imply that such craters should have uneven floors, not only indented to varying degrees by the several impacts but strewn with boulders and debris from the breakup of the meteorites themselves. 
(B) Large numbers of meteorites struck the lunar surface during the Moon's formation.
Orbits similar to that of the Earth-Moon system was quite large. Since the Moon, unlike the Earth, possesses no atmosphere, such bodies would reach the lunar surface at a higher velocity than they would reach Earth. 
(C) Meteorites are likely to penetrate the lunar surface.
 When a large body strikes the lunar surface, it is not stopped at the moment of impact but penetrates to a depth that depends on its mass, radius, and impact velocity.
(D) Some craters contain a central mountain peak.
 This liquefying of the rock at the moment of impact has also been put forward to explain the presence in some craters of a central mountain peak since we know, from high-speed photography of drops falling into liquids that a jet is formed in the center of an impact region.
 (E) The maria are devoid of large craters.
(no explanation given)

4. Which of the following statements about the meteorite-impact theory is most clearly supported by the information in the passage?

(A) It is more acceptable to scientists than is the volcanism theory.(volcanism theory is out of scope)
 (B) It is able to explain some observed features of the Moon's surface. 
(True) 
(C) It is one of several theories all of which seem equally tenable to scientists.
(equally tenable to scientists is not true. Refer last para:)
When a body the size and shape of a meteorite strikes solid rock it is quite probable that no intermediate liquid phase of the surface rock is ever produced.)
(D) Its importance is primarily historical. (historical is out of scope)
(E) It has been abandoned by most scientist (abondoning of theory is not mentioned)

5. The passage states that, in contrast to meteorites that enter the Earth's atmosphere meteorites striking the Moon are

(A) likely to be almost entirely burned up
(B) likely to fall close together
(C) likely to liquefy immediately
(D) able to create craters of widely varying diameters
 (E) able to hit the surface at greater speeds (true)

Since the Moon, unlike the Earth, possesses no atmosphere, such bodies would reach the lunar surface at a higher velocity than they would reach Earth

6. The author suggests that the theory that has been presented to explain the existence of central mountain peaks in some craters is based on

(A) the author's own observation of the behavior of lunar rock
(B) inadequate evaluations of the material structure of-the lunar crust
 (C) inference from an apparently similar situation 
(D) conjectures with which the author agrees
(E) information that has become outdated

This liquefying of the rock at the moment of impact has also been put forward to explain the presence in some craters of a central mountain peak since we know, from high-speed photography of drops falling into liquids that "a jet is formed in the center of an impact region."

7. The author considers an explanation for the formation of very large lunar craters and then evaluates the explanation as

(A) confirmed by the characteristics of meteorites as they travel through space
 (B) supported by observations concerning the liquefying of rocks (True) 
(C) incompatible, without further additions. with evidence of the smoothness of crater floors
(D) improbable because of a disparity with the known causes of analogous formations on Earth
(E) inconsistent if unmodified, with the facts about the distribution of the large lunar craters

Observation, however, suggests that the floors of large craters are smoother than can be accounted for by this theory unless there is some other mechanism whereby the floor becomes appreciably smoother following the impact.One mechanism that has been suggested is that those meteorites that formed the craters fell on the lunar surface when the Moon was in a semi plastic condition or, if they fell after the lunar crust had solidified, that the impact itself would liquefy the surface rock sufficiently to force it to flow rather like lava.

8. It can be inferred from the passage that unevenness in the floors of craters (Highlighted) should have resulted from the fact that

(A) the meteorites that formed the craters had different masses or impact velocities
(not given)
(B) the meteorites that formed the craters were all traveling at the same speed
(not given)
(C) the meteorites that formed the craters all reached the Moon's surface at the same time
(several meteorites fell "close together" (in space, although not necessarily in time)
(D) when the meteorites struck the Moon, its surface was in a semi plastic condition
(not given)
 (E) when the meteorites struck the Moon, its surface was already uneven (true)
-the meteors striking around the already impacted surface is what creates the uneven floor)
 
 If we are to explain the very large craters on the assumption that several meteorites fell close together (in space, although not necessarily in time), this would imply that such craters should have uneven floors, not only indented to varying degrees by the several impacts but strewn with bould

pintukr · Answer

1. According to the passage, one hypothesis proposed to explain the smoothness of the floors of large craters argues that the smoothness is a result of the

(A) disintegration of meteorites
 cause of uneven surface, not smoothness

(B) liquefying of surface rock
  listed as a reason for smoothness (refer paragraph 3)..CORRECT answer

(C) numerous impact of meteorites
 this is also a cause of uneven surface, not smoothness

(D) polar concentration of craters
 no such mention found in the passage

(E) frictional burning of matter
 this has been mentioned to explain the reduced impact of meteorites on earth's surface

2. The purpose of the first paragraph is to

(A) summarize the evidence supporting a scientific theory
 first paragraph is primarily a description of formation of large craters on the moon , and the suggested theory

(B) explain what is known about a scientific puzzle
In fact a theory has been presented along with description of phenomenon of large lunar craters

(C) introduce a theory that has been proved correct
 theory -- proved correct or otherwise -- can't be ascertained

(D) describe phenomena to be explained
  CORRECT ANSWER..first paragraph is primarily a description of formation of large craters on the moon , and the suggested theory

(E) clarify the meaning of an obscure statement
 Out of scope. No such obscure statement can be located in the 1st paragraph

3. The author fails to suggest any explanation for which of the following statements?

(A) There is little evidence of the breakup of meteorites on the floors of lunar craters.
 explanation suggested through existence of 'smooth' surface of large lunar craters

(B) Large numbers of meteorites struck the lunar surface during the Moon's formation.
 existence of large-sized craters

(C) Meteorites are likely to penetrate the lunar surface.
 impact of meteorites at high velocities

(D) Some craters contain a central mountain peak.
 liquefying of the rock --serves as the explanation

(E) The maria are devoid of large craters.
  no explanation located in the passage for the maria (the very large plains)being devoid of large craters..CORRECT answer

4. Which of the following statements about the meteorite-impact theory is most clearly supported by the information in the passage?

(A) It is more acceptable to scientists than is the volcanism theory.
 no comparative analysis of two theories presented in the passage

(B) It is able to explain some observed features of the Moon's surface.
  the theory pertaining to the impact of meteorites has been used to explain the phenomenon of lunar craters..CORRECT answer

(C) It is one of several theories all of which seem equally tenable to scientists.
 no comparative analysis of several theories -- presented in the passage; also, only two theories are presented in the passage

(D) Its importance is primarily historical.
 Out of scope stimulus

(E) It has been abandoned by most scientists.
 no such claim can be corroborated

5. The passage states that, in contrast to meteorites that enter the Earth's atmosphere meteorites striking the Moon are

(A) likely to be almost entirely burned up
 as per passage, no atmosphere on the moon --so, 'burning up' not possible

(B) likely to fall close together
 passage suggests that such occurrence may or may not be true

(C) likely to liquefy immediately
 not corroborated using the facts presented in the passage

(D) able to create craters of widely varying diameters
 the same is likely to be true for meteorites impacting Earth too

(E) able to hit the surface at greater speeds
  passage highlights that due to the absence of atmosphere, the meteorites striking the lunar surface are able to hit the surface at greater speeds..CORRECT answer

6. The author suggests that the theory that has been presented to explain the existence of central mountain peaks in some craters is based on

(A) the author's own observation of the behavior of lunar rock
 no mention of author's observation found in the passage

(B) inadequate evaluations of the material structure of-the lunar crust
 Out of scope, since no such evaluation cited

(C) inference from an apparently similar situation
  phenomenon pertaining to 'high-speed photography of drops falling into liquids' , an apparently similar situation, has been explained in 3rd paragraph..CORRECT answer

(D) conjectures with which the author agrees
 not based on a conjecture, rather a similar natural phenomenon has been cited

(E) information that has become outdated
 no such mention of an outdated piece of information

7. The author considers an explanation for the formation of very large lunar craters and then evaluates the explanation as

(A) confirmed by the characteristics of meteorites as they travel through space
 meterorites' travel through space has not been used to evaluate the explanation, rather the explanation has been cited as incompatible citing the smoothness of lunar crater floors

(B) supported by observations concerning the liquefying of rocks
 not supported..rather rejected on the basis of observations

(C) incompatible, without further additions. with evidence of the smoothness of crater floors
  the author rejects the explanation (as per the theory pertaining to action of meteorites) citing the smoothness of lunar crater floors..CORRECT answer

(D) improbable because of a disparity with the known causes of analogous formations on Earth
 such disparity has not been mentioned in the passage
 
(E) inconsistent if unmodified, with the facts about the distribution of the large lunar craters
 no facts related to the distribution of the large lunar craters found in the passage

8. It can be inferred from the passage that unevenness in the floors of craters (Highlighted) should have resulted from the fact that

(A) the meteorites that formed the craters had different masses or impact velocities
  'indented to varying degrees by the several impacts' as mentioned in paragraph 2 alludes to this inference..CORRECT answer

(B) the meteorites that formed the craters were all traveling at the same speed
 the opposite has been mentioned in the form of 'indented to varying degrees by the several impacts'.

(C) the meteorites that formed the craters all reached the Moon's surface at the same time
 no such claim can be corroborated from the passage

(D) when the meteorites struck the Moon, its surface was in a semi plastic condition
 semi-plastic condition has been mentioned to explain the smoothness, not uneven floors

(E) when the meteorites struck the Moon, its surface was already uneven
 no mention of such claim in the passage

Thus, BDEBECCA are The CORRECT answers to Q.1.2.3.4, 5, 6,7,8

$!vakumar.m · Answer

1. According to the passage, one hypothesis proposed to explain the smoothness of the floors of large craters argues that the smoothness is a result of the 
Two possible scenarios have been suggested to explain the smoothness of the floors - 
- first, the meteorites that formed the craters fell on the lunar surface when the Moon was in a semi plastic condition, or 
- Secondly, if they fell after the lunar crust had solidified, then the impact itself would liquefy the surface rock sufficiently to force it to flow rather like lava.
Option B is correct.

(C) introduce a theory that has been proved correct  
Not true, the theory of formation of lunar craters by the impact of large number of meteorites does not answer all the possible characteristics of craters.

(D) describe phenomena to be explained  
Option D is a strong contender to option B. However, since the formation of lunar craters and its characteristics has not been explained completely – so option B wins.
  (E) clarify the meaning of an obscure statement  
Not true – the problem definitions are clear and there is no ambiguity in them.

3. The author fails to suggest any explanation for which of the following statements?

(A) There is little evidence of the breakup of meteorites on the floors of lunar craters.  
Some explanation is provided in first and second paragraph on how the breakup of meteorites on the floors of lunar craters may make the surface uneven.

(B) Large numbers of meteorites struck the lunar surface during the Moon's formation.  
Again, this is explained in the first paragraph - “when, as seems possible, the number of meteoritic bodies moving in orbits similar to that of the Earth-Moon system was quite large”

(C) Meteorites are likely to penetrate the lunar surface.  
Relevant explanation is given in the first paragraph – “hen a large body strikes the lunar surface, it is not stopped at the moment of impact but penetrates to a depth that depends on its mass, radius, and impact velocity” and in the second paragraph – “such craters should have uneven floors, not only indented to varying degrees by the several impacts but strewn with boulders and debris from the breakup of the meteorites themselves. ”

(D) Some craters contain a central mountain peak.   
This is explained and also an analogy is drawn in the third paragraph – “This liquefying of the rock at the moment of impact has also been put forward to explain the presence in some craters of a central mountain peak since we know, from high-speed photography of drops falling into liquids that a jet is formed in the center of an impact region.”

(E) The maria are devoid of large craters.  
This is mentioned as one of the fact concerning moon surface in the first paragraph, however, the author fails to account for why the Maria are devoid of large craters. Option E is correct.

4. Which of the following statements about the meteorite-impact theory is most clearly supported by the information in the passage? 
  (A) It is more acceptable to scientists than is the volcanism theory.  
The passage just mentions the volcanism theory but never compares it with the meteorite impact theory. Also the passage describes the meteorite theory and explains some observed features of the lunar craters, however, not all of them. Option A is incorrect.

(B) It is able to explain some observed features of the Moon's surface.  
Option B is correct because the meteorite impact theory is able to explain why lunar craters are not distributed evenly over the lunar surface and why they also appear in a wide range of sizes. It is also mentioned in the passage that when a large body (or a group of meteorites) strikes the lunar surface, the impact results in craters with uneven floors, not only indented to varying degrees by the several impacts but strewn with boulders and debris from the breakup of the meteorites themselves. Thus, we see that the meteorite impact theory is able to explain some observed features of the Moon’s surface.

(C) It is one of several theories all of which seem equally tenable to scientists.  
It is one of several theories but the author has not commented upon if they are all equally tenable to scientists. Incorrect.

(D) Its importance is primarily historical.  
Option D is incorrect because this theory is still relevant and can be useful to explain some features of lunar craters.

(E) It has been abandoned by most scientists.  
Option E is incorrect because this theory is still relevant and also no evidence is given in the passage to say that the scientists have abandoned this theory.

5. The passage states that, in contrast to meteorites that enter the Earth's atmosphere meteorites striking the Moon are 
  (A) likely to be almost entirely burned up  
Option A is incorrect because it is mentioned in first paragraph that “They also would not be affected by frictional burning such as they would undergo when plunging through the terrestrial atmosphere.”

(B) likely to fall close together  
Option B is incorrect because no explanation or evidence is given in the paragraph that the meteorites striking the moon are likely to fall close together. However, the author has assumed the same to explain the very large craters.

(C) likely to liquefy immediately  
Option C is incorrect because although this has been used as a possibility in order to explain the reason for smooth surface of the lunar craters, the author towards the end of the passage clearly says that “When a body the size and shape of a meteorite strikes solid rock it is quite probable that no intermediate liquid phase of the surface rock is ever produced. “

(D) able to create craters of widely varying diameters  
Option D is incorrect because no explanation or evidence is given in the paragraph that the meteorites striking the moon are able to create craters of widely varying diameters in comparison to meteorites that enter the Earth’s atmosphere.

(E) able to hit the surface at greater speeds  
Option E is correct as explanation is given in the first paragraph – “Since the Moon possesses no atmosphere, the meteorites would reach the lunar surface at a higher velocity than they would reach Earth.”

6. The author suggests that the theory that has been presented to explain the existence of central mountain peaks in some craters is based on 
  (A) the author's own observation of the behavior of lunar rock  
Not true – the author clearly mentions that in high speed photography of drops falling into liquids such a jet is created in the center of an impact region.

(B) inadequate evaluations of the material structure of-the lunar crust  
Option B is incorrect as explained in option A.

(C) inference from an apparently similar situation  
Option C is correct because the author has drawn an analogy from high-speed photography of drops falling into liquids that creates a jet in the center of an impact region to explain the presence of a central mountain peak in some craters.

(D) conjectures with which the author agrees  
Not true as complete information is available on why a jet is formed in the central region of liquid when drops fall into it.

(E) information that has become outdated  
Not true because the author draws comparison with high-speed photography of drops falling into liquids and explains that in a similar manner the central mountain peaks would have been created on the impact of meteorites on lunar surface, while in semi plastic condition.

7. The author considers an explanation for the formation of very large lunar craters and then evaluates the explanation as 
An explanation for the formation of very large craters is based on the assumption that several meteorites fell close together and this would imply that such craters should have uneven floors. Observation, however, suggests that the floors of large craters are smoother than can be accounted for by this theory unless there is some other mechanism whereby the floor becomes appreciably smoother following the impact.
  (A) confirmed by the characteristics of meteorites as they travel through space  
In the explanation for the formation of very large craters, the author does not evaluate the explanation as complete to explain all the features of lunar craters. Also, the smooth surface of the craters is in question and not how the meteorites travel through space. Option A is incorrect.

(B) supported by observations concerning the liquefying of rocks  
Option B is incorrect because the author does not evaluate the explanation as complete to explain all the features of lunar craters. Also, the observations concerning the liquefying of rocks is explaining the presence of central mountain peaks in some of the craters but the liquefying of rocks theory itself is questioned by the author in the last paragraph.

(C) incompatible, without further additions. with evidence of the smoothness of crater floors  
From the explanation for the formation of very large craters in the second paragraph, we can see that the author evaluates the explanation as incompatible, that is, the meteorite impact theory is not providing an explanation for the smooth surface of the lunar craters. Hence, additional mechanism is needed to explain why the crater surface is smooth. Thus, option C is correct.

(D) improbable because of a disparity with the known causes of analogous formations on Earth  
Option D is incorrect because the author has not mentioned that the explanation for large craters is improbable. Also, the author in order to explain the presence in some craters of a central mountain peak has drawn parallel with formation of jet when drops fall into a liquid.

(E) inconsistent if unmodified, with the facts about the distribution of the large lunar craters  
Option E is incorrect because though the explanation is not complete, but it fails to provide explanation for smooth surface and not for the distribution of the large lunar craters.

8. It can be inferred from the passage that unevenness in the floors of craters (Highlighted) should have resulted from the fact that

(A) the meteorites that formed the craters had different masses or impact velocities 
It is mentioned in the passage that when a large body (or a group of meteorites) strikes the lunar surface, it is not stopped at the moment of impact but penetrates to a depth that depends on its mass, radius, and impact velocity. Thereby creating craters with uneven floors, not only indented to varying degrees by the several impacts but strewn with boulders and debris from the breakup of the meteorites themselves. Therefore, Option A is correct.

(B) the meteorites that formed the craters were all traveling at the same speed  
Not true. In that case the crater must have uniform surface.

(C) the meteorites that formed the craters all reached the Moon's surface at the same time  
Option C is incorrect because even if the meteorites reached the Moon’s surface at the same time they would have penetrated to a depth depending upon their mass, radius and speed.

(D) when the meteorites struck the Moon, its surface was in a semi plastic condition  
Option D is incorrect because it is given in the passage that if the Moon’s surface was in a semi plastic condition, then the impact of meteorites would have resulted in craters with smooth surface.

(E) when the meteorites struck the Moon, its surface was already uneven  
Not true because no such evidence is given in the passage.

Elite097 · Answer

1. According to the passage, one hypothesis proposed to explain the smoothness of the floors of large craters argues that the smoothness is a result of the

(A) disintegration of meteorites —  This is an explanation for large craters but not for smoothness

(B) liquefying of surface rock —  Third para says that a suggested mechanism is meteor Fallon fin moon in semi plastic stafe such “ that the impact itself would liquefy the surface rock sufficiently”

(C) numerous impact of meteorites —  Ae do not know about “numerous” impact of metered rites. We only know that they hit the surface Ar difference velocities and that doesn’t explain smoothness

(D) polar concentration of craters —  we have no info to substantiate this

(E) frictional burning of matter —  Passage states opposite “ They also would not be affected by frictional burning ”

Ans B

2. The purpose of the first paragraph is to

(A) summarize the evidence supporting a scientific theory -  theory is regarding lunar crater formation but no evidence has been provided regarding that rather the lack of evidence is the reason for various explanations

(B) explain what is known about a scientific puzzle —  we cannot say that it is a puzzle because lunar crater formation is just a scientific event. Also the puzzling element “evenness” has been only brought up in para 2

(C) introduce a theory that has been proved correct —  Two theories have been mentioned not one and they have not been proved correct but rather revised

(D) describe phenomena to be explained —-  Yes first para is setting the context for the remaining passage and gives context of the phenomenon (lunar crust formation) that is later being explained

(E) clarify the meaning of an obscure statement -  it is not clear what obscure statement is referring to

Ans D

3. The author fails to suggest any explanation for which of the following statements?

(A) There is little evidence of the breakup of meteorites on the floors of lunar craters-  Tricky but we have an explanation for this -“ this would imply that such craters should have uneven floors”

(B) Large numbers of meteorites struck the lunar surface during the Moon's formation-  We know “ the number of meteoritic bodies moving in orbits similar to that of the Earth-Moon system was quite large”

(C) Meteorites are likely to penetrate the lunar surface-  we know that meteors “ penetrates to a depth that depends on its mass, radius, and impact velocity”

(D) Some craters contain a central mountain peak-  We know “ explain the presence in some craters of a central mountain peak”

(E) The maria are devoid of large craters-  we are not given any explanation for this aspect as this just stated as a fact

Ans E

4. Which of the following statements about the meteorite-impact theory is most clearly supported by the information in the passage?

(A) It is more acceptable to scientists than is the volcanism theory-  No such comparison has been made

(B) It is able to explain some observed features of the Moon's surface-  All points stated regarding meteor theory have been disregarded for one or the other consideration such as unevenness vs smoothness, liquefying vs no liquid phase

(C) It is one of several theories all of which seem equally tenable to scientists-  yes since the 1st para mentions to theories without giving any preference hence that choice is correct

(D) Its importance is primarily historical-  No historical nature has been expressed

(E) It has been abandoned by most scientists-  We can see throughout the passage that it has been criticized but we cannot say that most scientists have abandoned it

Ans C

5. The passage states that, in contrast to meteorites that enter the Earth's atmosphere meteorites striking the Moon are

(A) likely to be almost entirely burned up —  rather we are told that there is no burning while entering the moon since it has no atmosphere

(B) likely to fall close together —  likeliness of falling together is not mentioned

(C) likely to liquefy immediately —  likeliness to liquify is not provided nor a comparison between earth and moon

(D) able to create craters of widely varying diameters —  no mention is made of diameters

(E) able to hit the surface at greater speeds -  yes first para states that “ Since the Moon, unlike the Earth, possesses no atmosphere, such bodies would reach the lunar surface at a higher velocity ”

And E

6. The author suggests that the theory that has been presented to explain the existence of central mountain peaks in some craters is based on

(A) the author's own observation of the behavior of lunar rock-  Author has not observed anything about this behaviour

(B) inadequate evaluations of the material structure of-the lunar crust-  No such evaluation was performed in the first place

(C) inference from an apparently similar situation-  Yes since we are told “ high-speed photography of drops falling into liquids that a jet is formed in the center of an impact region”

(D) conjectures with which the author agrees-  No conjecture or agreement has been presented

(E) information that has become outdated-  We don’t have information on whether info has become outdated

Ans C

7. The author considers an explanation for the formation of very large lunar craters and then evaluates the explanation as

The author takes the explanation of craters as the result of meteors and their debris striking the surface very close together however disregards it bevause that should lead to unevenness whereas the surface is actually smooth

(A) confirmed by the characteristics of meteorites as they travel through space -  As explained he goes against it

(B) supported by observations concerning the liquefying of rocks -  As explained above, he goes against it

(C) incompatible, without further additions. with evidence of the smoothness of crater floors -  yes the third para states “ Observation, however, suggests that the floors of large craters are smoother”

(D) improbable because of a disparity with the known causes of analogous formations on Earth-  the reason cited is not that there is disparity with known causes of analogous formations as we don’t know about analogous info

(E) inconsistent if unmodified, with the facts about the distribution of the large lunar craters-  formation has nothing to do with the distribution of large craters and hence no inconsistency is described

Ans C

8. It can be inferred from the passage that unevenness in the floors of craters (Highlighted) should have resulted from the fact that

(A) the meteorites that formed the craters had different masses or impact velocities -  yes cuz passage tells us “ this would imply that such craters should have uneven floors, not only indented to varying degrees by the several impacts”

(B) the meteorites that formed the craters were all traveling at the same speed -  this is exactly the opposite since we know they travel at different speeds

(C) the meteorites that formed the craters all reached the Moon's surface at the same time -  it is clearly mentioned “not necessarily in terms of time”

(D) when the meteorites struck the Moon, its surface was in a semi plastic condition -  this concept has been explained much later and also this is the reason for smoothness not unevenness

(E) when the meteorites struck the Moon, its surface was already uneven—  we are not told that surface was already uneven and that’s a cause for unevenness

Ans A

Catman · Answer

1. According to the passage, one hypothesis proposed to explain the smoothness of the floors of large craters argues that the smoothness is a result of the

(A) disintegration of meteorites  ~ Incorrect refer to the line "uneven floors, not only indented to varying degrees by the several impacts but strewn with boulders and debris from the breakup of the meteorites themselves" This is related to the uneven surface.
 
(B) liquefying of surface rock   ~ Correct refer to the line "One mechanism that has been suggested is that those meteorites that formed the craters fell on the lunar surface when the Moon was in a semi plastic condition or, if they fell after the lunar crust had solidified, that the impact itself would liquefy the surface rock sufficiently to force it to flow rather like lava." 
 
(C) numerous impact of meteorites  ~ Incorrect, it is shown why the surface should have uneven floors.

(D) polar concentration of craters  ~ Incorrect, polar concentration of craters is not mentioned.

(E) frictional burning of matter  ~ Incorrect, refer to the line "They also would not be affected by frictional burning"

2. The purpose of the first paragraph is to

(A) summarize the evidence supporting a scientific theory  ~ InCorrect, author is not solving the scientific puzzle.

(B) explain what is known about a scientific puzzle  ~ Incorrect, author is not solving the scientific puzzle.

(C) introduce a theory that has been proved correct  ~ Incorrect, thoery is not proof correct .

(D) describe phenomena to be explained  ~ Correct, refer to the line "Any explanation of crater formation must clearly take these facts into account"

(E) clarify the meaning of an obscure statement  ~ Incorrect, no obscure statement meaning is intended to be find .

3. The author fails to suggest any explanation for which of the following statements?

(A) There is little evidence of the breakup of meteorites on the floors of lunar craters.  ~ Incorrect, refer to the line "this would imply that such craters should have uneven floors, not only indented to varying degrees by the several impacts but strewn with boulders and debris from the breakup of the meteorites themselves"

(B) Large numbers of meteorites struck the lunar surface during the Moon's formation.  ~ Incorrect, refer to the line "According to the former theory, the large majority of the craters were formed during the early stages of the Moon's development when, as seems possible, the number of meteoritic bodies moving in orbits similar to that of the Earth-Moon system was quite large."

(C) Meteorites are likely to penetrate the lunar surface.  ~ Incorrect, refer to the line "Since the Moon, unlike the Earth, possesses no atmosphere, such bodies would reach the lunar surface at a higher velocity than they would reach Earth.
 
(D) Some craters contain a central mountain peak.  ~ Incorrect, refer to the line "his liquefying of the rock at the moment of impact has also been put forward to explain the presence in some craters of a central mountain peak"

(E) The maria are devoid of large craters.   ~ Correct, "The maria (the very large plains) are noticeably devoid of large craters." No explanation is given about this in the passage.

4. Which of the following statements about the meteorite-impact theory is most clearly supported by the information in the passage?

(A) It is more acceptable to scientists than is the volcanism theory.  ~ Incorrect, position of scientist about the theory is not mentioned.
 
(B) It is able to explain some observed features of the Moon's surface.   ~Correct, refer to the line "According to the former theory, the large majority of the craters were formed during the early stages of the Moon's development when, as seems possible" The theory is able to explain certain observed feature of the moon's surface.

(C) It is one of several theories all of which seem equally tenable to scientists.  ~ Incorrect, there are not several theories only 2 theory are mentioned.
 
(D) Its importance is primarily historical. ~  Incorrect, no historical data about the theory is mentioned.

(E) It has been abandoned by most scientists.  ~ Incorrect, position of scientist about the theory is not mentioned .

5. The passage states that, in contrast to meteorites that enter the Earth's atmosphere meteorites striking the Moon are

(A) likely to be almost entirely burned up  ~ Incorrect not mentioned.
 
(B) likely to fall close together  ~ Incorrect not mentioned.

(C) likely to liquefy immediately  ~ Incorrect not mentioned.

(D) able to create craters of widely varying diameters  ~ Incorrect not mentioned.

(E) able to hit the surface at greater speeds  ~ Correct, refer to the line "Since the Moon, unlike the Earth, possesses no atmosphere, such bodies would reach the lunar surface at a higher velocity than they would reach Earth."

6. The author suggests that the theory that has been presented to explain the existence of central mountain peaks in some craters is based on

(A) the author's own observation of the behavior of lunar rock  ~ Incorrect, author mentions later that "There is unfortunately, one very serious objection to this idea."

(B) inadequate evaluations of the material structure of-the lunar crust  ~ Correct, refer to the line "There is unfortunately, one very serious objection to this idea..When a body the size and shape of a meteorite strikes solid rock it is quite probable that no intermediate liquid phase of the surface rock is ever produced." So author is not agreeing with the explanation and objects the idea.

(C) inference from an apparently similar situation ~  Incorrect, no similar situation is discussed.

(D) conjectures with which the author agrees  ~ Incorrect, "There is unfortunately, one very serious objection to this idea." Author is not agreeing to this idea.

(E) information that has become outdated

7. The author considers an explanation for the formation of very large lunar craters and then evaluates the explanation as

(A) confirmed by the characteristics of meteorites as they travel through space ~  Incorrect, it is not confirmed by the characteristics of meteorites why the surface is smoother.

(B) supported by observations concerning the liquefying of rocks  ~ Incorrect liquefying of rocks is mentioned for smoother craters.
 
(C) incompatible, without further additions. with evidence of the smoothness of crater floors  ~ Correct, refer to the line "Observation, however, suggests that the floors of large craters are smoother than can be accounted for by this theory" . The theory unable to explain why the surface remains smoother after the impact.

(D) improbable because of a disparity with the known causes of analogous formations on Earth  ~ Incorrect no analogous formation on earth is compared.

(E) inconsistent if unmodified, with the facts about the distribution of the large lunar craters  ~ Incorrect author does not mention it's inconsistency if unmodified, it does not explain why the surface is still smoother which it should not be as per the theory.

8. It can be inferred from the passage that unevenness in the floors of craters (Highlighted) should have resulted from the fact that

(A) the meteorites that formed the craters had different masses or impact velocities  ~ Correct refer to the line "When a large body strikes the lunar surface, it is not stopped at the moment of impact but penetrates to a depth that depends on its mass, radius, and impact velocity."   
 
(B) the meteorites that formed the craters were all traveling at the same speed  ~ Incorrect not mentioned that they were travelling at the same speed.

(C) the meteorites that formed the craters all reached the Moon's surface at the same time  ~ Incorrect refer to the line "fell close together (in space, although not necessarily in time)"

(D) when the meteorites struck the Moon, its surface was in a semi plastic condition  ~ Incorrect, this observation was made to suggests that the floors of large craters are smoother than can be accounted for .

(E) when the meteorites struck the Moon, its surface was already uneven  ~ Incorrect, the surface became uneven after the impact, as per the theory.

Sajjad1994 · Answer

Explanation

1. According to the passage, one hypothesis proposed to explain the smoothness of the floors of large craters argues that the smoothness is a result of the

Explanation

The passage discusses two main theories concerning the origin of lunar craters, namely, impact of meteorites and volcanic activity. It notes that if the impact theory is correct, large craters should have uneven floors, but observations show that they are smoother than expected. The passage then suggests that one possible explanation for the smoothness of the floors is the liquefying of the surface rock due to the impact of meteorites. However, the passage notes a serious objection to this idea: that it is quite probable that no intermediate liquid phase of the surface rock is ever produced when a meteorite strikes solid rock. Therefore, the correct answer is  (B)  liquefying of surface rock.

Answer: B

Sajjad1994 · Answer

Explanation

2. The purpose of the first paragraph is to

Explanation

The purpose of the first paragraph is to describe the phenomena of lunar craters that need to be explained. The author notes that lunar craters are not evenly distributed and range in size from small to very large, with the large plains being noticeably devoid of large craters. The paragraph also introduces the two main theories about the origin of the craters, meteorite impact and volcanic activity, and notes that any explanation of crater formation must take into account the observed facts about their distribution and size. Therefore, the correct answer is  (D) , "describe phenomena to be explained."

Answer: D

Sajjad1994 · Answer

Explanation

3. The author fails to suggest any explanation for which of the following statements?

Explanation

The passage mentions that craters on the Moon are not distributed evenly, and that the maria, which are the large plains, are noticeably devoid of large craters. The author discusses two main theories for the origin of lunar craters: meteorite impacts and volcanic activity. However, the author does not provide any explanation for why the maria are devoid of large craters. The passage does not mention any specific theories or explanations for this observation.

(A)  The passage discusses the fact that the floors of large craters are smoother than expected based on the theory of meteorite impacts, but it does not suggest any explanation for the breakup of meteorites on the floors of lunar craters.

(B)  The passage discusses the theory that large numbers of meteorites struck the lunar surface during the Moon's formation as a possible explanation for the origin of lunar craters.

(C)  The passage discusses the fact that meteorites are likely to penetrate the lunar surface, which is relevant to the theory of meteorite impacts as a possible explanation for the origin of lunar craters.

(D)  The passage discusses the theory that the central mountain peaks found in some craters may be explained by the liquefying of the surface rock at the moment of impact.

(E)  The passage mentions the observation that the maria are noticeably devoid of large craters but does not provide any explanation for this observation.

Answer: E

Sajjad1994 · Answer

Explanation

4. Which of the following statements about the meteorite-impact theory is most clearly supported by the information in the passage?

Explanation

The passage discusses two theories regarding the origin of lunar craters: meteorite impact and volcanic activity. The passage suggests that the meteorite-impact theory is more likely than the volcanic theory to account for the observed distribution and sizes of lunar craters. The passage describes how meteorites would have impacted the Moon's surface differently than they would have impacted the Earth's surface because the Moon lacks an atmosphere, which would have slowed them down and burned them up. The passage also suggests that the meteorite-impact theory can explain some observed features of the Moon's surface, such as the distribution and sizes of craters, and offers potential mechanisms for the formation of central mountain peaks and smoothed crater floors.

Therefore, the statement that is most clearly supported by the information in the passage is  (B)  "It is able to explain some observed features of the Moon's surface."

Answer: B

Sajjad1994 · Answer

Explanation

5. The passage states that, in contrast to meteorites that enter the Earth's atmosphere meteorites striking the Moon are

Explanation

The passage compares the effects of meteorites striking the Moon versus those striking the Earth. The Moon lacks an atmosphere, so meteorites that strike the Moon are not affected by frictional burning and hit the surface at higher speeds than they would on Earth. This is stated in the following sentence: "Since the Moon, unlike the Earth, possesses no atmosphere, such bodies would reach the lunar surface at a higher velocity than they would reach Earth." Therefore, option  (E)  is the correct answer.

Option (A)  is incorrect because the passage does not mention anything about meteorites being burned up upon entering the Moon's atmosphere because it does not have one.

Option (B)  is incorrect because the passage does not suggest that meteorites falling close together is unique to the Moon.

Option (C)  is incorrect because while the passage discusses the theory that the lunar surface may liquefy upon impact, it also states that there is a serious objection to this idea.

Option (D)  is incorrect because although the passage mentions that lunar craters come in a wide range of sizes, it does not imply that meteorites striking the Moon are the only possible cause of craters with varying diameters.

Answer: E

Sajjad1994 · Answer

Explanation

6. The author suggests that the theory that has been presented to explain the existence of central mountain peaks in some craters is based on

Explanation

The passage discusses the two main theories concerning the origin of lunar craters, one involving meteorite impacts and the other involving volcanic activity. The author then goes on to discuss the possibility that central mountain peaks in some craters were formed by the impact of meteorites, which could liquefy the surface rock at the moment of impact. However, the author notes that there is a serious objection to this idea, namely that a body the size and shape of a meteorite striking solid rock may not produce an intermediate liquid phase.

The question asks what the theory presented to explain the central mountain peaks is based on. The passage indicates that the theory is based on the idea that meteorite impacts could liquefy the surface rock at the moment of impact, which could explain the presence of central mountain peaks. Therefore, the correct answer is  (C)  inference from an apparently similar situation.

Answer: C

Sajjad1994 · Answer

Explanation

7. The author considers an explanation for the formation of very large lunar craters and then evaluates the explanation as

Explanation

The author presents two main theories for the origin of lunar craters: meteorite impact and volcanic activity. The former theory proposes that most craters were formed during the early stages of the Moon's development when there were many meteoritic bodies in orbits similar to that of the Earth-Moon system. The author notes that large craters should have uneven floors if several meteorites fell close together, but observation suggests that the floors of large craters are smoother than can be accounted for by this theory unless there is some other mechanism whereby the floor becomes appreciably smoother following the impact. The author suggests that the impact itself liquefies the surface rock sufficiently to force it to flow like lava, but notes that there is one serious objection to this idea: when a meteorite strikes solid rock, it is quite probable that no intermediate liquid phase of the surface rock is ever produced.

The question asks us to evaluate the author's explanation for the formation of very large lunar craters. The explanation is that the impact of meteorites liquefies the surface rock sufficiently to force it to flow like lava. The author notes that there is one serious objection to this idea: when a meteorite strikes solid rock, it is quite probable that no intermediate liquid phase of the surface rock is ever produced. Therefore, the explanation is incompatible, without further additions, with evidence of the smoothness of crater floors. Thus, the correct answer is (C) incompatible, without further additions, with evidence of the smoothness of crater floors.

Answer: C

Sajjad1994 · Answer

Explanation

8. It can be inferred from the passage that unevenness in the floors of craters (Highlighted) should have resulted from the fact that

Explanation

The passage discusses the fact that large craters on the Moon have smooth floors, which cannot be accounted for by the theory that they were formed by several meteorites falling close together. The passage then suggests that one possible explanation for the smooth floors is that the meteorites fell on the Moon when it was in a semi-plastic condition or that the impact itself liquefied the surface rock, causing it to flow like lava. However, the passage also notes that it is quite probable that no intermediate liquid phase of the surface rock is ever produced when a body the size and shape of a meteorite strikes solid rock.

Therefore, it can be inferred that the unevenness in the floors of craters should have resulted from the fact that the meteorites that formed the craters had different masses or impact velocities, as these factors would affect how deep the meteorites would penetrate the surface and how much material would be displaced. Therefore, the correct answer is  (A)  the meteorites that formed the craters had different masses or impact velocities.

Answer: A

consistentprep · Answer

7) (B) supported by observations concerning the liquefying of rocks:
While the passage does discuss the idea of liquefaction, it doesn't confirm the theory. Instead, it presents the liquefaction hypothesis as a potential explanation, but this is ultimately questioned (as unlikely due to the nature of meteorite impacts). - eliminate

C) the passage discusses the meteorite impact theory and presents a potential mechanism to explain the smooth floors of large lunar craters. The theory suggests that when meteorites struck the Moon, they may have caused the surface rock to liquefy, thereby creating smoother floors. However, the passage evaluates this mechanism by stating that the floors of large craters are smoother than expected given the theory, unless another mechanism (like liquefaction of the surface rock) is introduced.

That lunar craters are not distributed evenly over the lunar surface

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Reading Comprehension (RC) Questions

That lunar craters are not distributed evenly over the lunar surface

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards