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# A small number of the forest species of lepidoptera (moths and butterf

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Intern
Joined: 19 May 2019
Posts: 4
A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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25 Oct 2019, 08:55
daagh wrote:
Q1.
RC00120-06. It can be inferred from the passage that the mortality caused by agents such as predatory birds or parasites was measured in an attempt to

(A) develop an explanation for the existence of lepidoptera population cycles
(B) identify behavioral factors in lepidoptera that affect survival rates
(C) identify possible methods for controlling Lepidoptera population growth
(D) provide evidence that lepidoptera populations are self-regulating
(E) determine the life stages of lepidoptera at which mortality rates are highest

As far as I see, Q1 is not about any viral connection. It is about population cycles and the reason for those cycles before anyone knew how they occurred. The virus is only figuring in the later part of the story. It has nothing to do with the earlier attempts to know why the cycles occurred.
I didn't get your point on the difference between a CR rationale and RC rationale. There can be only one rationale. What holds true for CR must be true for RC too.

daagh my bad! I should have included the question

RC00120-01. Which of the following, if true, would most weaken the author’s conclusion in lines 18-22?

(A) New research reveals that the number of species of birds and parasites that prey on lepidoptera has dropped significantly in recent years.
(B) New experiments in which the habitats of lepidoptera are altered in previously untried ways result in the shortening of lepidoptera population cycles.
(C) Recent experiments have revealed that the nuclear polyhedrosis virus is present in a number of predators and parasites of lepidoptera.
(D) Differences among the habitats of lepidoptera species make it difficult to assess the effects of weather on lepidoptera population cycles.
(E) Viral disease is typically observed in a large proportion of the lepidoptera population.

daagh wrote:
I didn't get your point on the difference between a CR rationale and RC rationale. There can be only one rationale. What holds true for CR must be true for RC too.

What I meant is that in regular CRs, we have a given set of information i.e. the argument in the form of premises and conclusions and we clearly know we have to refer to it.
No doubts in the fact that the kind of logic and reasoning we apply to CR and "CRs in RC" will be the same. My question is What should we consider as an argument in these "CRs in RC"?
The whole passage? or only the part of passage till the highlighted conclusion?
I know that in some passages, premises relevant to a conclusion may be found till the last line of the passage. But this particular passage is peculiar in that it lists discoveries and findings and so the conclusions drawn from them in chronological manner. At least in this case, my basic CR instinct tells me to disregard the virus and all information related to it as it has not been mentioned till the conclusion. Is my instinct correct?
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Joined: 19 May 2019
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A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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25 Oct 2019, 09:45
carcass wrote:

It is true that the virus is not mentioned until you initiate the second paragraph but the first paragraph contains crucial information not only to solve the first question but the others.

Also, it usually includes the main idea, and more often than not, we are talking Official RC passage because the NON-official material does not have the same consistency, the first paragraph has information which are related to other information that could be even at the end of the passage. We do not know this until we read the Rc in its entirety.

I.E, the GMAT RCs are conceived in a way you look at the entire story. E.G TOEFL passages are suitable, to some extent, to the strategy you have suggested.

Regard

carcass I get your point that the passage as whole is to be considered for any question related to it.

RC00120-01. Which of the following, if true, would most weaken the author’s conclusion in lines 18-22?

(A) New research reveals that the number of species of birds and parasites that prey on lepidoptera has dropped significantly in recent years.
(B) New experiments in which the habitats of lepidoptera are altered in previously untried ways result in the shortening of lepidoptera population cycles.
(C) Recent experiments have revealed that the nuclear polyhedrosis virus is present in a number of predators and parasites of lepidoptera.
(D) Differences among the habitats of lepidoptera species make it difficult to assess the effects of weather on lepidoptera population cycles.
(E) Viral disease is typically observed in a large proportion of the lepidoptera population.

Just to be sure, for this question, if I use any information related to the virus provided in the passage to eliminate an option and reach an answer, then it's OK right? I should not dump an option just because it mentions the virus and the virus has not been mentioned in any premise related to the conclusion?
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Joined: 01 Sep 2010
Posts: 3411
Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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25 Oct 2019, 10:08
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Top Contributor
The real secret to putting a bullet in the head of an RC passage is simple enough: understand the passage. Improve your standard English. read onece but carefully, though skip the details (they are there just as fluff).

Understand the big picture. The answer will be solved in a snap. Right away.

Regards
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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25 Oct 2019, 10:14
1
Top Contributor
TheDarKKKnighT wrote:
carcass wrote:

It is true that the virus is not mentioned until you initiate the second paragraph but the first paragraph contains crucial information not only to solve the first question but the others.

Also, it usually includes the main idea, and more often than not, we are talking Official RC passage because the NON-official material does not have the same consistency, the first paragraph has information which are related to other information that could be even at the end of the passage. We do not know this until we read the Rc in its entirety.

I.E, the GMAT RCs are conceived in a way you look at the entire story. E.G TOEFL passages are suitable, to some extent, to the strategy you have suggested.

Regard

carcass I get your point that the passage as whole is to be considered for any question related to it.

RC00120-01. Which of the following, if true, would most weaken the author’s conclusion in lines 18-22?

(A) New research reveals that the number of species of birds and parasites that prey on lepidoptera has dropped significantly in recent years.
(B) New experiments in which the habitats of lepidoptera are altered in previously untried ways result in the shortening of lepidoptera population cycles.
(C) Recent experiments have revealed that the nuclear polyhedrosis virus is present in a number of predators and parasites of lepidoptera.
(D) Differences among the habitats of lepidoptera species make it difficult to assess the effects of weather on lepidoptera population cycles.
(E) Viral disease is typically observed in a large proportion of the lepidoptera population.

Just to be sure, for this question, if I use any information related to the virus provided in the passage to eliminate an option and reach an answer, then it's OK right? I should not dump an option just because it mentions the virus and the virus has not been mentioned in any premise related to the conclusion?

Wait: in this case the instruction are clear: you have to go to that line and weaken the conclusion. If then the virus comes to play it depends
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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29 Oct 2019, 06:01
1
1
RC00120-05.The primary purpose of the passage is to
(A) describe the development of new techniques that may help to determine the driving force behind population cycles in lepidoptera
(B) present evidence that refutes a particular theory about the driving force behind population cycles in lepidoptera
(C) present a hypothesis about the driving force behind population cycles in lepidoptera
(D) describe the fluctuating patterns of population cycles in Lepidoptera
(E) question the idea that a single driving force is behind population cycles in Lepidoptera

I got confused between B and C. Can someone explain why B is wrong.

GMATNinja

The key to answering primary purpose questions is to understand the purpose of each piece of the passage, and determine how these pieces connect to one another. This passage breaks down nicely into paragraphs, so let's go through each one:

• Paragraph 1: The author introduces the idea of population cycles, and then states that attempts to determine the driving force behind these cycles have been "unproductive." These attempts focused on several different factors -- predatory birds and parasites, changes in habitat, etc.
• Paragraph 2: The author introduces another potential "driving force" -- viruses. He/she then explains the mechanisms behind this theory
• Paragraph 3: The author provides additional support for the theory that viruses are the driving force behind population cycles.

When taken together, it is clear that the author's primary purpose is to introduce and explain the evidence behind a new theory -- the information in the first paragraph is included to provide additional context for the new hypothesis. Let's see how that stacks up against the answer choices in question:

Quote:
(B) present evidence that refutes a particular theory about the driving force behind population cycles in lepidoptera

There are a couple of issues with this answer choice. First the author does not refute a "particular theory" -- he/she states that inquiries into several potential theories have been unproductive. In addition, the author's primary purpose is not to refute these other theories. Instead, he/she wants to discuss a new theory (that viruses are the driving force behind population cycles). For these reasons, (B) is out.

Quote:
(C) present a hypothesis about the driving force behind population cycles in lepidoptera

Here we go! The "hypothesis" is that viruses are the driving force behind population cycles in lepidoptera. While the author does discuss other theories, he/she includes these in the passage to provide context for the virus hypothesis -- so we can say that the "primary purpose" of the passage is to present the new hypothesis.

I hope that helps!
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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06 Dec 2019, 00:39
GMATNinja wrote:
RC00120-05.The primary purpose of the passage is to
(A) describe the development of new techniques that may help to determine the driving force behind population cycles in lepidoptera
(B) present evidence that refutes a particular theory about the driving force behind population cycles in lepidoptera
(C) present a hypothesis about the driving force behind population cycles in lepidoptera
(D) describe the fluctuating patterns of population cycles in Lepidoptera
(E) question the idea that a single driving force is behind population cycles in Lepidoptera

I got confused between B and C. Can someone explain why B is wrong.

GMATNinja

The key to answering primary purpose questions is to understand the purpose of each piece of the passage, and determine how these pieces connect to one another. This passage breaks down nicely into paragraphs, so let's go through each one:

• Paragraph 1: The author introduces the idea of population cycles, and then states that attempts to determine the driving force behind these cycles have been "unproductive." These attempts focused on several different factors -- predatory birds and parasites, changes in habitat, etc.
• Paragraph 2: The author introduces another potential "driving force" -- viruses. He/she then explains the mechanisms behind this theory
• Paragraph 3: The author provides additional support for the theory that viruses are the driving force behind population cycles.

When taken together, it is clear that the author's primary purpose is to introduce and explain the evidence behind a new theory -- the information in the first paragraph is included to provide additional context for the new hypothesis. Let's see how that stacks up against the answer choices in question:

Quote:
(B) present evidence that refutes a particular theory about the driving force behind population cycles in lepidoptera

There are a couple of issues with this answer choice. First the author does not refute a "particular theory" -- he/she states that inquiries into several potential theories have been unproductive. In addition, the author's primary purpose is not to refute these other theories. Instead, he/she wants to discuss a new theory (that viruses are the driving force behind population cycles). For these reasons, (B) is out.

Quote:
(C) present a hypothesis about the driving force behind population cycles in lepidoptera

Here we go! The "hypothesis" is that viruses are the driving force behind population cycles in lepidoptera. While the author does discuss other theories, he/she includes these in the passage to provide context for the virus hypothesis -- so we can say that the "primary purpose" of the passage is to present the new hypothesis.

I hope that helps!

A Lucid and beautiful explanation as always
Re: A small number of the forest species of lepidoptera (moths and butterf   [#permalink] 06 Dec 2019, 00:39

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