There are two main theories concerning the origin of the lunar craters

Question

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 semiplastic 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 impacts of meteorites
(D) polar concentration of craters
(E) frictional burning of matter

2 
 2. 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.

3 
 3. 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

4 
 4. 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

5 
 5. 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

6 
 6. It can be inferred from the passage that unevenness in the floors of craters should have resulted from the fact that

(A) the meteorites that formed the craters had different masses of 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 fur face at the same time
(D) when the meteorites struck the Moon, its surface was in a semiplastic condition
(E) when the meteorites struck the Moon, its surface was already uneven

zhanbo · Accepted Answer

Question 1 : My answer is  (B) 
The floors of large craters are smoother than expected. Two hypotheses are suggested: (1) those meteorites that formed the craters fell on the lunar surface when the Moon was in a semiplastic condition (2) the impact itself would liquefy the surface rock sufficiently to force it to flow rather like lava.
(B) designates the second hypothesis.

Question 2 : My answer is  (B) .
The last paragraph points out a serious objection to the idea of the meteorite impact theory: the impact itself may not have liquefied the surface rock sufficiently or at all. Still, the meteorite impact theory may still work by claiming that those meteorites that formed the craters fell on the lunar surface when the Moon was in a semiplastic condition, or by some other hypotheses to be discussed in the ensuing texts. 
(A) No such claim is made. (though the ensuing texts will cover volcanism theory for sure.)
(B) Yes indeed. That is what this reading is about. For example, it can explain "the presence in some craters of a central mountain peak"
(C) "several theories"?  Several  in reading comprehension should mean more than two. (In CR,  several  can mean two or more.) Also, we cannot support that they are  equally  tenable to scientists. 
(DE) No such claim is made.

Question 3 : My answer is  (E) .
In the reading, "Since the Moon, unlike the Earth, possesses no atmosphere, such bodies would reach the lunar surface at a higher velocity (=speed) than they would reach Earth. "

Question 4:  My answer is  (C) .
In the reading, "since we know, from high-speed photography of drops falling into liquids, that a jet is formed in the center of an impact region".
(C) indicates that.

Question 5 : My answer is  (C) .
This question concerns itself in the second paragraph. 
Reread the paragraph and see that (C) is the correct answer.

Question 6 : My answer is  (A) 
In the reading, "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. "
Or through POE
(B) "at the same speed"? No scientists would say that.
(C) "at the same time"? Only in fantasy land.
(D) This can help explain evenness of the floors not  unevenness . 
(E) Not mentioned.

ElninoEffect · 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

Only option B has been discussed or has been provided as a reason for the smoothness of the moon crater.
(A) disintegration of meteorites
 (B) liquefying of surface rock 
(C) numerous impacts of meteorites
(D) polar concentration of craters
(E) frictional burning of matter

2. 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. .
If anything just the opposite is true.
(B)  It is able to explain some observed features of the Moon’s surface. 
Yes it can be infered.
(C) It is one of several theories all of which seem equally tenable to scientists.
Only two theories have been presented.
(D) Its importance is primarily historical. -
We cannot infer that.
(E) It has been abandoned by most scientists.
We cannot infer that.

3. 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
Just the opposite.
(B) likely to fall close together
We cannot infer that can be cannot be.
(C) likely to liquefy immediately
Just the opposite.
(D) able to create craters of widely varying diameters
We cannot infer that.
 (E) able to hit the surface at greater speeds 
Due to the absence of the atmosphere yes this is correct and has been discussed.

4. 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
since we know, from 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
Comparison with proof has been made.
(E) information that has become outdated
We cannot infer that.

5. 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 
This option only provides the right characteristic of the explanation.
(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

6. It can be inferred from the passage that unevenness in the floors of craters should have resulted from the fact that

(A) the meteorites that formed the craters had different masses of impact velocities  
Exactaly have been discussed;
(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 fur face at the same time
(D) when the meteorites struck the Moon, its surface was in a semiplastic condition
(E) when the meteorites struck the Moon, its surface was already uneven

Archit3110 · 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  correct option
(C) numerous impacts of meteorites
(D) polar concentration of craters
(E) frictional burning of matter

2. 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. . 
facts and information more given about meteorite 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.

3. 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  ; no atmosphere like earth on moon

4. 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 
not much info provided to say conclusively
(C) inference from an apparently similar situation
(D) conjectures with which the author agrees
(E) information that has become outdate

5. 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 given 
(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

6. It can be inferred from the passage that unevenness in the floors of craters should have resulted from the fact that

(A) the meteorites that formed the craters had different masses of 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 fur face at the same time
 (D) when the meteorites struck the Moon, its surface was in a semiplastic condition 
discussed in the passage 
(E) when the meteorites struck the Moon, its surface was already uneven

sshwetima · 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  - stated in 2nd paragraph
(C) numerous impacts of meteorites
(D) polar concentration of craters
(E) frictional burning of matter

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

Used POE for this question

(A) It is more acceptable to scientists than is the volcanism theory.  - not mentioned anywhere, although only one theory is discussed 
 (B) It is able to explain some observed features of the Moon’s surface.  - though it has tried to explain large craters formation but smoothened surface is not fully understandable  
 (C) It is one of several theories all of which seem equally tenable to scientists.  - as per author - 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.
 (D) Its importance is primarily historical.  -  not stated
 
 (E) It has been abandoned by most scientists.  -  not stated
 
 3. 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 speed.  - as per passage - "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."

4. 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  - analogy of high speed drops of liquid is used
(D) conjectures with which the author agrees
(E) information that has become outdated

5. 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  - 4th paragraph is used for that
(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

6. It can be inferred from the passage that unevenness in the floors of craters should have resulted from the fact that

(A) the meteorites that formed the craters had different masses of impact velocities  - it is mentioned that when body strikes lunar surface, impact of penetration depend on mass, radius and impact velocity 
(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 fur face at the same time
(D) when the meteorites struck the Moon, its surface was in a semiplastic condition
(E) when the meteorites struck the Moon, its surface was already uneven

Hoozan · Answer

P1: Two major theories that explain the lunar craters: (1) impact of meteorites and (2) volcanic activity. It then goes ahead to explain theory (1) in detail.

P2: Explains a shortcoming of theory (1) - "The craters are smoother than expected" - and then goes on to suggest that this shortcoming could be avoided - "unless there is some other mechanism"

P3: Explains the "mechanism" mentioned in P2 thereby undermining the shortcoming of theory (1)

P4: The author shares his views by stating that the mechanism is flawed.

Note: The author DOES NOT undermind the Theory. He simply rejects the mechanism that was explaining a possible shortcoming of theory (1)

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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

"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 semiplastic 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."

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

Correct Answer: (B)
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2. Which of the following statements about the meteorite impact theory is most clearly supported by the information in the passage?

Quote:

(A) It is more acceptable to scientists than is the volcanism theory.

Incorrect "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." The passage clear mentions that both the theories are the major ones. There is no preference between the two

Quote:

(B) It is able to explain some observed features of the Moon’s surface.

HOLD I don't have any reason to eliminate this choice. So I will keep this on hold and then consider this one.

(C) It is one of several theories all of which seem equally tenable to scientists.

Incorrect As mentioned in (B) There are only two theories that have got the majority of the attention

Quote:

(D) Its importance is primarily historical.

Incorrect Nowhere stated in the passage

Quote:

(E) It has been abandoned by most scientists.

Incorrect As mentioned in (B) This is one of the two major theories that is considered as a possible explanation

Looking at (C) I believe it is the correct answer. Why? because P1 talks about the "impact of meteorite". It further states some details that could explain the reason for the presence of craters. "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.

Correct Answer: (C)
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3. 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 - Correct - 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."

Correct Answer: (E)
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4. 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 - Correct - This is the essence of P4 "There is, unfortunately, one very serious objection to this idea."
(C) inference from an apparently similar situation
(D) conjectures with which the author agrees
(E) information that has become outdated

Correct Answer: (A)
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5. 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 - Correct - For this simply check the summary of the passage. P2 explains a shortcoming of the theory. P3 explains a mechanism that undermines this shortcoming. P4 rejects this shortcoming. Choice (C) is a pretty cool summary of P1 P2 and P3
(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

Correct Answer: (C)
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6. It can be inferred from the passage that unevenness in the floors of craters should have resulted from the fact that

(A) the meteorites that formed the craters had different masses of 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 fur face at the same time - Correct - "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"
(D) when the meteorites struck the Moon, its surface was in a semiplastic condition
(E) when the meteorites struck the Moon, its surface was already uneven

Correct Answer: (C)

Sorry but I was on a time crunch. Tried to be as detailed as possible. I hope this helps

100mitra · Answer

Words:   390 
  Read Time:   4 mins – 30 sec
  Correct:   5/6
  Paragraph Structure:   Highlight and discussion about the theories, favouring to one of them. 
  Paraphrasing:  
 Para 1:  Highlights a theory related to lunar craters, which is created due to impact of meteorites that depends on meteorites mass, radius, and impact velocity.
 Para 2:  Assumption craters should have un-even floor or observation suggests smoother floor following the impact.
 Para 3:  Craters would have created due to impact of meteorites during initial stage of the moon’s development, resulting crater to behave like liquefying property, just as a jet is formed in the center of an impact region
 Para 4:  Authors contrast opinion about para 3

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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   – wrong   (Not discussed in the passage)
  (B) liquefying of surface rock – correct, as per para 2, theory I and by observation feedback   
(C) numerous impacts of meteorites   – wrong   , trap! It’s a assumption, which authors indicates as flaw
(D) polar concentration of craters   – wrong   (out of scope)
(E) frictional burning of matter   – wrong   (opposite to what is mentioned in the para1)

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2. Which of the following statements about the meteorite impact theory is most clearly supported by the information in the passage?  
  (B) It is able to explain some observed features of the Moon’s surface – as explained in para 1, about theory I  
 Eliminate A, C, D and E – not discussed in the passage, irrelevant or out of scope 
(A) It is more acceptable to scientists than is the volcanism theory 
(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

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

as mentioned in the passage,  
1. “ 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 ”
2. “ 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 .”
  Correct option: (E) able to hit the surface at greater speeds

Eliminate rest, as it doesn’t show comparison between meteorites hitting Earth and Moon 
(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

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4. The author suggests that the theory that has been presented to explain 
the existence of central mountain peaks in some craters is based on  
 as mentioned in para 3 : 
“ 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 ”
  Correct option: (C) inference from an apparently similar situation

Eliminate B, and E   –  Irrelevant and Out of scope, as this information is not available in the passage 
(B) inadequate evaluations of the material structure of the lunar crust
(E) information that has become outdated

Eliminate A, and D   –  Author does not have his own observation as in A, and in D Author denies the agreement as mentioned in para 4 
(A) the author's own observation of the behavior of lunar rock
(D) conjectures with which the author agrees

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5. The author considers an explanation for the formation of very large lunar craters and then evaluates the explanation as  
 Para 2: 
1.   Assumption  that several meteorites fell close together 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 . 
2.   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 ”
 Para 3:  
“  Mechanism Suggestion  is that those meteorites that formed the craters fell on the lunar surface when the Moon was in a semiplastic 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 ”
 Para 4 : 
“  Objection to para 3 : 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

Correct Option: (C) incompatible, without further additions, with evidence of the smoothness of crater floors

Eliminate A, D, and E   – Irrelevant, out of scope or not mentioned in the passage for justification
(A) confirmed by the characteristics of meteorites as they travel through space
(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

Eliminate Option B,   as it is opposite to what it has mentioned in the passage
(B) supported by observations concerning the liquefying of rocks

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6. It can be inferred from the passage that 
unevenness in the floors of craters should have resulted from the fact that

as mentioned in the passage, Para 2  
“ If we are to explain the very large craters on the assumption that 
several meteorites fell close together, this would imply that 
such craters  should have uneven floors , 
not only  indented to varying degrees by the several impacts  
but also strewn with boulders and debris from the breakup of the meteorites themselves .”

Correct Option: (A) the meteorites that formed the craters had different masses of impact velocities

Eliminate B, and C   – Out of scope, not mentioned in the Passage.
(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

Eliminate D, and E   – it mentions the information mentioned in the passage, but does not highlights the reason for un-even structure of the surface of the moon
(D) when the meteorites struck the Moon, its surface was in a semiplastic condition
(E) when the meteorites struck the Moon, its surface was already uneven

Ccccc1111111 · 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(OA)
(C) numerous impacts of meteorites
(D) polar concentration of craters
(E) frictional burning of matter
something makes the impact less severe>>>"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 semiplastic 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. "
<possibility>
1. the Moon is not solidified.
2. the impact itself would liquefy.

2. 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. (not even discuss how the volcanism theory works)
(B) It is able to explain  some  observed features of the Moon’s surface.(OA)
(C) It is one of several theories all of which seem equally tenable to scientists. (not equally tenable: only talk about the meteorite impact theory)
(D) Its importance is primarily historical. (x)
(E) It has been abandoned by most scientists. (no one object. only author is talking.)

(B) It is able to explain some observed features of the Moon’s surface.
 some  means not every
so the meteorite impact theory may fall to explain the relationship between big holes and the impacts of several meteorites, but the theory still can explain other features

3. 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(OA)

in contrast to  meteorites that enter the Earth’s atmosphere
the earth has a buffer to slow down impacts of meteorites, that is, the Moon has not a buffer to slow down impacts of meteorites

4. 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(OA)
(D) conjectures with which the author agrees
(E) information that has become outdated

why author adds some new item in the article?
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. 
since we know: use a daily phenomenon to explain a hard science principle.

5. 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(OA)
(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

author starts with one hypothesis, and then say the premise of hypothesis can not be possible ( can not explain the smoothness of crater floors) 
in other word, the hypothesis is wrong.

6. It can be inferred from the passage that unevenness in the floors of craters should have resulted from the fact that

(A) the meteorites that formed the craters  had different masses  of impact velocities(OA)
(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 fur face at the same time
(D) when the meteorites struck the Moon, its surface was in a semiplastic condition
(E) when the meteorites struck the Moon, its surface was already uneven

in this question, be careful of what the question ask. "unevenness in the floors of craters should have resulted from the fact that..."
not the discussion of smoothness

also not the discussion of the very large craters or several meteorites falling close together 
 unevenness  is 
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.

uneven  floors, 
1. not only indented to  varying degrees  by the several impacts (how uneven floors form)
2. but strewn with boulders and debris from the breakup of the meteorites themselves. (other effects the impacts of the meteorites cost)

nikitathegreat · Answer

Can someone explain Q4 - what is a similar situation here? isnt the author is saying that basis the photograph also we see similar results however that is not a situation?

GMATNinja  @VeritasKarishma

Thanks

GMATNinja · Answer

Question 4 
 
To explain a theory behind the existence of central mountain peaks in some craters on the moon, the author presents a comparison: when drops fall into liquids, a jet is formed in the center of an impact region. So, maybe rocks liquify at the moment of impact and behave in the same way.

The two "situations" here are 1) meteors hitting the moon craters, and 2) drops hitting a liquid. From these two "apparently" similar situations, you can infer an explanation for the mountain peaks.

(C) is the correct answer to question 4.

I hope that helps!

VerbalBot · Answer

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There are two main theories concerning the origin of the lunar craters

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There are two main theories concerning the origin of the lunar craters

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