Caterpillars of all species produce an identical hormone called "juvenile hormone" that maintains feeding behavior. Only when a caterpillar has...
GMAT Critical Reasoning : (CR) Questions
Caterpillars of all species produce an identical hormone called "juvenile hormone" that maintains feeding behavior. Only when a caterpillar has grown to the right size for pupation to take place does a special enzyme halt the production of juvenile hormone. This enzyme can be synthesized and will, on being ingested by immature caterpillars, kill them by stopping them from feeding.
Which of the following, if true, most strongly supports the view that it would not be advisable to try to eradicate agricultural pests that go through a caterpillar stage by spraying croplands with the enzyme mentioned above?
Passage Analysis:
| Text from Passage | Analysis |
| Caterpillars of all species produce an identical hormone called "juvenile hormone" that maintains feeding behavior. |
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| Only when a caterpillar has grown to the right size for pupation to take place does a special enzyme halt the production of juvenile hormone. |
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| This enzyme can be synthesized and will, on being ingested by immature caterpillars, kill them by stopping them from feeding. |
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Argument Flow:
The passage moves from explaining a natural biological process (hormone controls feeding) to describing the timing mechanism (enzyme stops hormone at right time) to revealing how this can be weaponized (artificial enzyme kills young caterpillars). This sets up the scientific foundation for understanding why spraying this enzyme might seem like a good pest control idea.
Main Conclusion:
There is no explicit conclusion in this passage - it's purely informational, providing the scientific background needed to evaluate whether using this enzyme as a pesticide would be advisable.
Logical Structure:
This is a descriptive passage that builds understanding step by step: universal hormone function → natural control mechanism → artificial application. Each statement adds a layer of biological knowledge that will be essential for evaluating the pest control strategy in the question.
Prethinking:
Question type:
Strengthen - We need to find information that would support the view that spraying croplands with the enzyme is NOT advisable for eradicating agricultural pests
Precision of Claims
The argument presents scientific facts about caterpillar biology and enzyme effects. The key claim we need to strengthen is that using this enzyme spray would be inadvisable for pest control
Strategy
Since we need to strengthen why spraying the enzyme would be inadvisable, we should think of negative consequences or problems that would make this pest control method impractical, harmful, or ineffective. We need scenarios that show why this seemingly good solution actually has serious drawbacks
Most species of caterpillar are subject to some natural predation. This doesn't strengthen the argument against using enzyme spray. If anything, natural predation might make the enzyme spray seem less necessary, but it doesn't provide a compelling reason why spraying would be inadvisable. Natural predation and artificial enzyme control could coexist without creating problems.
Many agricultural pests do not go through a caterpillar stage. This actually weakens the concern about using enzyme spray rather than strengthening it. If many pests aren't caterpillars, then the enzyme method would have limited scope but wouldn't necessarily be inadvisable for the pests it could target.
Many agriculturally beneficial insects go through a caterpillar stage. This perfectly strengthens the argument against enzyme spraying. Since the passage tells us that caterpillars of ALL species produce the identical hormone and the enzyme affects ALL caterpillars, spraying would kill beneficial insects along with pests. This collateral damage to helpful insects (like butterflies that pollinate crops) would make the method inadvisable despite its effectiveness against pest caterpillars.
Since caterpillars of different species emerge at different times, several sprayings would be necessary. This suggests the method would be inconvenient or costly, but inconvenience alone doesn't make something inadvisable - it just makes it less efficient. This is a practical concern but not a strong argument against the method.
Although the enzyme has been synthesized in the laboratory, no large-scale production facilities exist as yet. This addresses current production limitations but doesn't provide a fundamental reason why the method would be inadvisable. Production facilities could be built, so this is a temporary logistical issue rather than an inherent problem with the approach.