More selective than most chemical pesticides in that they ordinarily d

Question

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  Passage-04    GMATPrep RCs-Collection (Main article) 
   More selective than most chemical pesticides in that they ordinarily destroy only unwanted species, biocontrol agents (such as insects, fungi, and viruses) eat, infect, or parasitize targeted plant or animal pests. However, biocontrol agents can negatively affect nontarget species by, for example, competing with them for resources: a biocontrol agent might reduce the benefits conferred by a desirable animal species by consuming a plant on which the animal prefers to lay its eggs.  Another example of indirect negative consequcnces occurred in England when a virus introduced to control rabbits reduced the amount of open ground (because large rabbit populations reduce the ground cover), in turn reducing underground ant nests and triggering the extinction of a  blue butterfly  that had depended on the nests to shelter its offspring . The paucity of known extinctions or disruptions resulting from indirect interactions may reflect not the infrequency of such mishaps but rather the failure to look for or to detect them: most organisms likely to be adversely affected by indirect interactions are of little or no known commercial value and the events linking a biocontrol agent with an adverse effect are often unclear. Moreover, determining the potential risks of biocontrol agents before they are used is difficult, especially when a nonnative agent is introduced, because, unlike a chemical pesticide, a biocontrol agent may adapt in unpredictable ways so that it can feed on or otherwise harm new hosts.   1 
 D 
1. The passage is primarily concerned with

(A) explaining why until recently scientists failed to recognize the risks presented by biocontrol agents.

(B) emphasizing that biocontrol agents and chemical pesticides have more similarties than differences.

(C) suggesting that only certain biocontrol agents should be used to control plant or animal pasts.

(D) arguing that biocontrol agents involve risks, some of which may not be readily discerned.

(E) suggesting that mishaps involving biocontrol agents are relatively commonplace.

2 
 E 
2. The passage suggests that the author would be most likely to agree with which of the following statements about the use of biocontrol agents?

(A) Biocontrol agent should be used only in cases where chemical pesticides have proven ineffective or overly dangerous.

(B) Extinctions and disruptions resulting from the use of biocontrol agents are likely to have increasingly severe commercial consequences.

(C) The use of biocontrol agents does not require regulation as stringent as that required by the use of chemical pesticides.

(D) The use of biocontrol agents may even-finally supersede the use of chemical pesticides in controlling unwanted species.

(E) The risks of using native biocontrol agents may be easier to predict than the risks of using nonnative biocontrol agents.

3 
 D 
3. Which of the following is mentioned in the passage as an indirect effect of using a biocontrol agent?

(A) Reduction of the commercial value of a desirable animal species

(B) An unintended proliferation of a nontarget animal species

(C) An unforeseen mutation in a target species

(D) Diminution of the positive effects conferred by a nontarget animal species

(E) Competition for resources with a larger species

4 
 B 
4. The example presented by the author in highlight text most clearly serves to illustrate

(A) a situation in which a species is less vulnerable to biocontrol agents than it would have been to chemical pesticides.

(B) a way in which the introduction of a biocontrol agent can affect a nontarget species.

(C) a nonnative agent's adapting in an unpredictable way that results in damage to a new host.

(D) The contention that biocontrol agents can harm nontarget species by competing with them for resources.

(E) the way in which indirect consequences from the use of biocontrol agents are most likely to occur.

5 
 C 
5. According to the passage, which of the following is a concern that arises with biocontrol agents but not with chemical pesticides?

(A) Biocontrol agents are likely to destroy desirable species as well as undesirable ones.

(B) Biocontrol agents are likely to have indirect as well as direct adverse effects on nontarget species.

(C) Biocontrol agents may change in unforeseen ways and thus be able to damage new hosts.

(D) Biocontrol agents may be ineffective in destroying targeted species.

(E) Biocontrol agents may be effective for only a short period of time.

6 
 A 
6. The passage suggests which of the following about the  blue butterfly  mentioned in the highlighted text?

(A) The blue butterfly's survival was indirectly dependent on sustaining a rabbit population of a particular size.

(B) The blue butterfly's survival was indirectly dependent on sustaining large amounts of vegetation in its habitat.

(C) The blue butterfly's survival was threatened when the ants began preying on its offspring.

(D) The blue butterfly was infected by the virus that had been intended to control rabbit populations.

(E) The blue butterfly was adversely affected by a biocontrol agent that competed with it for resources.

mallya12 · Answer

Why q6 Option B is wrong. "the extinction of a blue butterfly that had depended on the nests to shelter its offspring. " I didn't understand nests of what??

GMATNinja · Answer

The chain of events is a bit confusing on this one! Let's organize the information from the passage:

A virus was introduced to control the rabbit population 
 Large rabbit populations REDUCE ground cover (and "vegetation" is another word for "ground cover"). So, controlling the rabbit population INCREASED vegetation 
 Increasing vegetation REDUCED underground ant nests 
 The blue butterflies depended on underground ant nests to shelter their offspring. So, reducing the underground ant nests led to the extinction of the butterflies

Question #6 asks us what the passage suggests above the blue butterflies.

Here is answer choice (B):
 
From the information above, we know that the exact opposite of answer choice (B) is true. The blue butterflies depended on underground ants nests, which depended on  reduced  vegetation. For this reason, answer choice (B) is out.

I hope that helps!

Chinmin123 · Answer

Hello,
For Qs 3 i got confused between B and D since they've clearly stated an example of the butterfly and its extinction for B. Hence i chose B. Can someone kindly clear my doubt?

Posted from my mobile device

thangvietnam · Answer

the passage is easy to read and understand. but to answer questions requires you to find out the place in the passage, which yield the information in the correct answer. positioning the place is time consuming and require patience. if you are hurried, you die. once you find the place, you can be confident with your choice.

the challenging is the fine the place in the passage dense with details and information.

the challenging is the fine the place in the passage dense with details and information.

dcummins · Answer

SajjadAhmad

Hi mate, there are multiple typos in the OP

Q3 E should be "with a larger species"

Q4 E should be "occur"

GMATNinja · Answer

Question 3 asks us to identify which choice is mentioned in the passage as an indirect effect of using a biocontrol agent.

Here's choice (B):

This choice does not state any example outright, so we shouldn't fill in that information as a reason for keeping the choice around.

Instead, (B) tells us that the  unintended proliferation of a nontarget animal species  is  an indirect effect  of using a biocontrol agent. Proliferation means rapid increase, and there's no evidence for that taking place in the passage:

The highlighted example describes what happened when rabbits were targeted by a biocontrol agent. 
  After the biocontrol agent (a virus) was introduced, two nontarget animal species were affected: ants and blue butterflies. 
  The indirect effect on ants was that underground ant nests were  reduced . 
  The indirect effect on the blue butterfly was  extinction .

Reduction goes in the opposite direction of proliferation, and extinction is basically as far as you can get from proliferation. This is why (B) must be eliminated.

Here's choice (D):

Again, this choice does not state any example outright, and never mentions the butterfly. We need to be precise when confirming whether this matches the passage.

Fortunately, when we check the passage, choice (D) is a spot-on match for what the author has written:

This is why we keep (D) as the correct choice.

I hope this helps!

PreiteeRanjan · Answer

WHY in Q-6 answer cant be B?
Kindly clarify?

GMATNinja · Answer

Please check out  this  post and let us know if you have further questions.

I hope that helps!

thangvietnam · Answer

this scenario is called "easy passage, close answers".
in this situation, we well meet an easy passage , which we can understand it with easy. but the questions are hard, specifically, the questions 2,3 and 4, contain 2 answer choices which are close. both these choices look correct but one of them contain ONE wrong word. realizing to find ONE WRONG WORD is key

Manicks · Answer

Question 3, why can't it be option E?

Diya52 · Answer

Can someone explain why Q3 option E is incorrect? is it because the passage only says that bio-control agents compete with non-target species for resources and not "larger species" per se?

Q4. Why is option E wrong?

Q5. Is option B wrong because the passage does not mention anything about bio-control agents having "direct adverse effects"?

GMATNinja · Answer

That's right! The author tells us that biocontrol agents can negatively affect  nontarget  species by competing with them for resources. However, the author NEVER mentions  larger  species. That's why we eliminate (E).

Question 4 
 
Here's the highlighted text that Q4 asks us to analyze:

Another example of indirect negative consequences occurred in England when a virus introduced to control rabbits reduced the amount of open ground (because large rabbit populations reduce the ground cover), in turn reducing underground ant nests and triggering the extinction of a  blue butterfly  that had depended on the nests to shelter its offspring.

In this scenario, the introduction of a biocontrol agent (a virus to control rabbits) led to a change in habitat (less ground cover), which in turn suppressed an unrelated structure in that habitat (underground ant nests), which in turn led to the extinction of a nontarget species (blue butterfly) that depended on the structure to survive (using the ant nests to shelter butterfly offspring).

Choice (E) states that this example most clearly serves to illustrate "the way in which indirect consequences from the use of biocontrol agents are most likely to occur."

But is the author trying to show us that indirect consequences of biocontrol agents  most likely happen in this way ?

Biocontrol agent for species A changes habitat 
  Change in habitat suppresses an unrelated structure built by species B 
  Suppression of unrelated structure leads to extinction of species C

Nope! This is simply  one of many ways  that indirect consequences can occur. The highlighted example is preceded by a description of a different scenario and followed by an admission that we lack information about extinctions and disruptions resulting from indirect interactions.

That's why we eliminate (E). Choice (B) remains the most accurate description of why the author brings up this highlighted example.

Question 5 
 
Let's make sure we're 100% clear on what the question is asking:

5. According to the passage, which of the following is a concern that arises with biocontrol agents but not with chemical pesticides?

The correct answer choice will reflect what the author tells us is a concern that DOES arise with biocontrol agents but DOES NOT arise with chemical pesticides. And the passage gives us our answer pretty explicitly:

...unlike a chemical pesticide, a biocontrol agent may adapt in unpredictable ways so that it can feed on or otherwise harm new hosts.

The correct answer choice should also identify this specific difference: Biocontrol agents can adapt in unpredictable ways, while chemical pesticides cannot adapt. Choice (C) is the only choice that matches up, which is why we keep it.

Now, here's choice (B) again:

(B) Biocontrol agents are likely to have indirect as well as direct adverse effects on nontarget species.

You're right to point out that the author never mentions whether biocontrol agents have direct adverse effects on nontarget species. However, we can also eliminate (B) based on the fact that this choice does NOT identify what the author plainly tells us is a key difference between biocontrol agents and chemical pesticides.

I hope this helps!

vaibhav99 · Answer

Can someone please help me with explanation of question 1?

Thanks for your help.

Posted from my mobile device

Sajjad1994 · Answer

Please read earlier response in below link https://gmatclub.com/forum/more-selecti ... l#p1395308 Hope it helps

RashedVai · Answer

Would you please explain how (A) is correct?  minustark

Posted from my mobile device

minustark · Answer

Too many rabbits >>> lost of vegetation or ground cover
To control those rabbits>>> introduction of virus
Virus reduced the rabbits >> so now more ground cover and less open ground (too much grassland)
Ants need open ground for their nests (less vegetation is preferred for ant nests)
And blue butterflies need ant nests
So, the less ground cover or vegetation, the better for our blue butterfly. And since rabbits helped to keep more open grounds, their survival was required for the butterflies.

mSKR · Answer

It took me a while to differentiate B vs E. 
E is one way how indirect consequence is most likely to occur. The example given is one way that matches to E
B says what is the intention of author to use this example. 
So B matches the question asked.

pretty close

Thanks  GMATNinja  for Q4 clarification

nikitathegreat · Answer

How is open ground linked to ground cover(vegetation)? when a virus is introduced, it reduced the amount of open ground? What does this mean?
I understand the point that when virus is introduced, rabbits die and hence ground cover increases because rabbits consume ground cover
when a virus introduced to control rabbits reduced the amount of open ground (because large rabbit populations reduce the ground cover),

Raman109 · Answer

For Question 2 - Look at this part of the passage - Moreover, determining the potential risks of biocontrol agents before they are used is difficult, especially when a nonnative agent is introduced. So, between the native and non-native, non-native is difficult to predict. Now let's look at option E - The risks of using native biocontrol agents may be easier to predict than those of nonnative biocontrol agents. The word easier is deceptive. Easier doesn't mean it's easier in general. It says between the two, it's easier. Other options, A and C, are not even mentioned in the passage.

For question 3 - We are being asked -the "indirect effect." Look at option D - Diminution of the positive effects conferred by a nontarget animal species. It matches the passage - "a biocontrol agent might reduce the benefits conferred by a desirable animal species." Option E is misleading as the passage never spoke about the "LARGER" species. Moreover, we are looking for an "indirect effect."

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More selective than most chemical pesticides in that they ordinarily d

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More selective than most chemical pesticides in that they ordinarily d

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