More selective than most chemical pesticides in that they ordinarily

Question

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 
 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 
 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 
 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 
 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 
 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 
 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.

JarvisR · Accepted Answer

Time Taken: 10 mins.
 1. The passage is primarily concerned with
A. explaining why until recently scientists failed to recognize the risks presented by biocontrol agents.
Nope.Nothing like that has been mentioned. 
B. emphasizing that biocontrol agents and chemical pesticides have more similarties than differences.
>>Nope.Nothing like that has been mentioned. 
C. suggesting that only certain biocontrol agents should be used to control plant or animal pasts.
>>Nope,no preferance regarding any particular agent has been mentioned.
D. arguing that biocontrol agents involve risks, some of which may not be readily discerned.
 "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" 
E. suggesting that mishaps involving biocontroll agents are relatively commonplace.
Nope.

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

3. Which of the following is mentioned in the passage as an indirect effect of using a biocontrol agent?
D. Diminution of the positive effects conferred by a nontarget animal species.
 "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."

4. The example presented by the author in highlight text most clearly serves to illustrate
B. a way in which the introduction of a biocontrol agent can affect a nontarget species.
 "...in turn reducing underground ant nests and triggering the extinction of a blue butterfly that had depended on the nests to shelter its offspring."

5. According to the passage, which of the following is a concern that arises with biocontrol agents but not with chemical pesticides?
C. Biocontrol agents may change in unforeseen ways and thus be able to damage new hosts.
 "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."
 
6. The passage suggests which of the following about the blue butterfly (highlight) mentioned in the highlighted text?
A. The blue butterfly's survival was indirectly dependent on sustaining a rabbit population of a particular size.

rohitmanglik · Answer

In Q6, I was stuck between A & E

A: BBfly's survival was indeed indirectly dependent on sustaining rabbit population. sustaining rabbit pop = no virus introduction = no reduction in ant nests = no BBfly extinction

E: BBfly was indeed badly affected by the virus that competed with it for resources (ant nests).

What's wrong with E?

Harley1980 · Answer

Hello,  rohitmanglik 
The E says that "The blue butterfly was adversely affected by a biocontrol agent that competed with it for resources."

But in the passage we don't have information about such biocontrol agent that compete with butterflies. The virus kills rabbits and as a consequence reduce open ground and as a consequence reduce the number of ants nests and butterflies need these nests for their children.

So we don't have any biological agent who competes with butterflies for resources.

A says that "The blue butterfly's survival was indirectly dependent on sustaining a rabbit population of a particular size." and this is true because we see a consequence of indirect influences from virus to butterflies.

Amit0507 · Answer

Wondering why can't the ans for Q6 be D- " The blue butterfly was infected by the virus that had been intended to control rabbit populations. "?

The passage clearly states that - " 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 "

Is it because the butterfly wasn't  infected but  impacted by the consequences?

Linhbiz · Answer

I think the word here is  infected  - BB doesn't get infected by the virus, its population is indirectly reduced.

Here might be a line of reason in my opinion:

Virus -> kill rabbit --> reduce rabbit number --> reduce open ground --> reduce underground ant nests --> reduce BB laying egg place --> reduce BB population.

There is no direct cause from Virus -> BB (but a series of consequence event in between). So the answer (A) is more appropriate in this sense:

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

sgrover18 · Answer

Hi Rohit,

I fell in the same trap and this trap is placed purposefully in the answer choices ( its not really a random choice). Now let me help you understand.

The passages states the following :
However, biocontrol agents can negatively affect nontarget species by, for example, competing withthem 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 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.

So the author has actually stated two negative consequences:
1. Competing with resources - the agents eat up the plant where the egss are laid
2. Since the virus was introduced to control rabit's population which led to decrease in the underground nests which subsequently affected the butterflies.

The butterflies are actually an example of another negative consequence, which we could generalise as an unforeseen indirect connection.

The best way to avoid this mistake is to read the passage or rather each sentence just the way we read the SC questions. Be sure you understand the purpose/meaning of the statement ( if you start understanding the use of modifiers , punctuations and lists, RCs will start getting easier). Let me know if this helps.

Regards,
Shradha

wadepooja9 · Answer

________________
Why is A wrong in Qs No 5?

GMATNinja · Answer

They ask for a concern that arises with biocontrol agents but NOT with chemical pesticides. Refer to the first sentence of the passage: "More selective than most chemical pesticides in that they ordinarily destroy only unwanted species, biocontrol agents..." So biocontrol agents ordinarily destroy only unwanted species. This implies that chemical pesticides destroy both unwanted species and other wanted species.

Chemical pesticides are likely to destroy desirable species as well as undesirable ones, so choice (A) represents a concern for BOTH chemical pesticides and biocontrol agents. Thus, (A) should be eliminated.

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

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!

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!

VerbalBot · Answer

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