Caterpillars of all species produce an identical hormone called "juven

Caterpillars of all species produce an identical hormone called “juvenile hormone” that maintains feeding behavior.

All caterpillars produce the same “juvenile hormone” (I wonder why it is called juvenile – which means immature or young!). This hormone maintains the eating behavior of the caterpillars.

Only when a caterpillar has grown to the right size for pupation to take place

I don’t know what pupation is. Perhaps, it’s a stage of development for caterpillars. I understand that there is a ‘right size’ for pupation to happen. The statement says that only when a caterpillar reaches this stage. Then what?

does a special enzyme halt the production of juvenile hormone.

Only then a special enzyme halts the production of juvenile hormone. So, before a caterpillar reaches this stage (grown to the right size for pupation to happen), this special enzyme doesn’t halt the production of juvenile hormone. (Given that juvenile hormone maintains eating behavior, I wonder what would happen once its production is halted! How would a caterpillar maintain its feeding behavior?)

This enzyme can be synthesized and will, on being ingested by immature caterpillars, kill them by stopping them from feeding.

This enzyme can be produced artificially and will kill the caterpillar if it is ingested by immature caterpillars. How will it kill them? By stopping them from feeding. (This makes sense since we’re already given that juvenile hormone maintains feeding behavior and that the production of juvenile hormone is halted by the enzyme. Thus, if this enzyme is ingested, the production of the juvenile hormone will stop, and the feeding behavior will not be maintained.)





Which of the following, if true, –

“If true” means that we’re supposed to take the option statements at face value; we’re not supposed to question their validity or truth value.

most strongly supports the view-

We’re looking for an option that most strongly supports a particular view. Since it says “most strongly supports”, we can have multiple options supporting the view, but we’re looking for an option that supports the view most strongly.*

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?

The view is that it would NOT be advisable to kill agricultural pests that go through a caterpillar stage by spraying the enzyme mentioned above on the croplands.
(The passage said that the enzyme can be produced artificially and will kill immature caterpillars on being ingested, but the view is that it would not be advisable to do so.)

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We’re looking for an option that most strongly GOES AGAINST spraying the enzyme on the cropland to kill the agricultural pests that go through a caterpillar stage.

Predicting Possible Answers -

We’re looking for a disadvantage of spraying the enzyme on the cropland to kill the agricultural pests that go through a caterpillar stage.

I can think of the following:

1. Perhaps, spraying this enzyme on the cropland harms the cropland in some way.
2. Perhaps, immature caterpillars of agricultural pests will not ingest anything from outside. We’re given that the enzyme needs to be ingested by an immature caterpillar. What if that doesn’t happen in the case of agricultural pests? (They’re smart!)

Before I evaluate options, I make sure that I’m very clear about what I’m looking for in the options. Do you also do so?

I’m looking for an option that supports the view. Which view? The view that it would NOT be advisable to kill agricultural pests that go through a caterpillar stage by spraying the enzyme mentioned above on the croplands.

(A) Most species of caterpillar are subject to some natural predation.

Incorrect. This option has NO IMPACT on the view.

The option says that some caterpillars of most species are killed by natural predators.

Even if some caterpillars are killed this way, why shouldn’t we kill the remaining caterpillars of agricultural pests by spraying the enzyme?

This option doesn’t give any reason for this. Thus, this option has no impact on the view.

(B) Many agricultural pests do not go through a caterpillar stage.

Incorrect.This option has no impact on the view. Why?

Because the view pertains to killing the agricultural pests that go through a caterpillar stage. (Did you miss this?!)

Even if many pests do not go through a caterpillar stage, the view is not impacted.

(C) Many agriculturally beneficial insects go through a caterpillar stage.

Correct. A very important word in this option is “beneficial”.

If there are agriculturally beneficial insects that go through a caterpillar stage, spraying the enzyme on the cropland may harm the cropland by killing these beneficial insects.

Thus, we have a reason to argue against spraying the enzyme on the cropland. Therefore, this option supports the view.

(D) Since caterpillars of different species emerge at different times, several sprayings would be necessary.

Incorrect. The fact that several sprayings would be necessary to kill the caterpillars of the pests presents a disadvantage. Thus, this option supports the view.

However, compared to option C, this option presents a much less serious disadvantage. While the disadvantage presented in option C doesn’t seem to be possible to overcome, the disadvantage presented in this option is not a significant one. Perhaps, doing the spraying several times is not an issue – it is perhaps very convenient and inexpensive. Or, perhaps, we spray only once and choose to eradicate only some of the pests.

Without being given any serious disadvantage of several sprayings, this option has a very mild effect on the view.

Thus, while this option supports the view, it is nowhere as strong as option C in supporting the view.

(E) Although the enzyme has been synthesized in the laboratory, no large-scale production facilities exist as yet.

Incorrect. This option has NO IMPACT on the view.

This option suggests that we don’t currently have a sufficient amount of enzyme to spray on the cropland. However, not having the enzyme currently CANNOT be a reason to argue that we should not use it to kill agricultural pests.

For example, you may not have an iPhone right now. However, this fact cannot be a reason to support that you SHOULD NOT use an iPhone to make calls.

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*In more than 90% of these questions, there is only one option that supports; other options have no impact or weaken. However, this particular question falls into the less than 10% category; it has two options that support the view

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By the way, have you heard of the caterpillar and butterfly story? It’s a very beautiful story. You can read it here: The Caterpillar And The Butterfly – International Story