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Most of the year, the hermit thrush, a North American songbird, eats

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Re: Most of the year, the hermit thrush, a North American songbird, eats [#permalink] Most of the year, the hermit thrush, a North American songbird, eats   29 May 2022, 22:28
Thanks MartyTargetTestPrep and why not B
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Re: Most of the year, the hermit thrush, a North American songbird, eats [#permalink] Most of the year, the hermit thrush, a North American songbird, eats   29 May 2022, 22:51
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Elite097 wrote:
Thanks MartyTargetTestPrep and why not B

(B) doesn't really change anything. Regardless of what nutrients the insect contain that berries don't, it could be that the reason the thrushes eat the berries is that berries contain nutrients that the thrushes need and insects lack.

Also, the fact that the passage says that thrushes have been eating insects "for most of the year" helps to make (B) incorrect since it's possible that any nutrients that thrushes get from insects but not from berries the thrushes have loaded up on already.
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Re: Most of the year, the hermit thrush, a North American songbird, eats [#permalink] Most of the year, the hermit thrush, a North American songbird, eats   30 May 2022, 09:36
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WillGetIt wrote:
Most of the year, the hermit thrush, a North American songbird, eats a diet consisting mainly of insects, but in autumn, as the thrushes migrate to their Central and South American wintering grounds, they feed almost exclusively on wild berries. Wild berries, however, are not as rich in calories as insects, yet thrushes need to consume plenty of calories in order to complete their migration. One possible explanation is that berries contain other nutrients that thrushes need for migration and that insects lack.

Which of the following, if true, most seriously calls into question the explanation given for the thrush’s diet during migration?


(A) Hermit thrushes, if undernourished, are unable to complete their autumn migration before the onset of winter.

(B) Insect species contain certain nutrients that are not found in wild berries.

(C) For songbirds, catching insects requires the expenditure of significantly more calories than eating wild berries does.

(D) Along the hermit thrushes’ migration routes, insects are abundant throughout the migration season.

(E) There are some species of wild berries that hermit thrushes generally do not eat, even though these berry species are exceptionally rich in calories.



Elite097

Most of the other posts in this thread label the explanation as the conclusion. I think that if we apply the "Why Test," we can see that probably isn't the case. If we use the explanation as the conclusion and ask "why," we can't use the rest of the argument as the premise(s). Quite the opposite; the explanation is exactly that: the explanation. And that means it isn't the conclusion. Okay, so what's the conclusion? Must be the thing that's being explained.

Conclusion:
Rest of year: eat insects while not migrating
Autumn: eat wild berries while migrating even though insects have more calories

WHY?
The premise offered by the argument is that berries contain nutrients needed for migration that insects lack.

We are asked what might call that premise into question.

There are two things in play here: calories and nutrients. We are told that calories are needed for migration. We are trying to call into question the explanation for why the birds eat berries instead of insects during migration. Is it that berries have other nutrients? Or is there some other explanation?

Since the questions in this thread mostly hinge on B, C, and D, I'll stick to those:
(B) Insect species contain certain nutrients that are not found in wild berries.
Are those nutrients necessary for migration? If not, and if the nutrients in berries are necessary for migration, it would certainly make sense for the birds to switch to berries during migration.
(C) For songbirds, catching insects requires the expenditure of significantly more calories than eating wild berries does.
Calories are critical for migration. Insects contain more calories but also cost SIGNIFICANTLY more calories to acquire (be alert when GMAC uses intensity words like "significant" - it's usually not just a filler word for them). Chasing insects might not be the way the birds want to use their energy while migrating. Take the (pun intended) low-hanging fruit and keep moving.
(D) Along the hermit thrushes’ migration routes, insects are abundant throughout the migration season.
This does the opposite of providing an explanation for why they eat berries. If there are so many insects, how do we get to the conclusion that they eat berries during migration?

Answer choice C
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Re: Most of the year, the hermit thrush, a North American songbird, eats [#permalink] Most of the year, the hermit thrush, a North American songbird, eats   20 Jul 2022, 07:43
Hi - two quick questions

Even though not an available option - i was wondering if this was also weakener (i was expecting this)

Quote:
 (option F) In the autumn, all the insects disappear underground - Thus insects are not accessible in the autumn


#2

Quote:
 Would you agree that option C does raise a follow-up. How much is the net calories gained if the hermits have insects vs. net calories gained if the hermits have berries. We need to compare this

Given we don't know this information -- C can't be chosen
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Re: Most of the year, the hermit thrush, a North American songbird, eats [#permalink] Most of the year, the hermit thrush, a North American songbird, eats   24 Jul 2022, 20:06
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jabhatta2 wrote:
Hi - two quick questions

Even though not an available option - i was wondering if this was also weakener (i was expecting this)

Quote:
 (option F) In the autumn, all the insects disappear underground - Thus insects are not accessible in the autumn


#2

Quote:
 Would you agree that option C does raise a follow-up. How much is the net calories gained if the hermits have insects vs. net calories gained if the hermits have berries. We need to compare this

Given we don't know this information -- C can't be chosen

Regarding the additional answer choice: adding in your own options generally isn't worth the time. It can actually hurt your accuracy in answering the question, because instead of just assessing the options on the page, you're (on some level) trying to find the answer that you've developed yourself. This can cause you to overlook options -- like (C) -- that are correct, but don't match your "expected" answer.

For your second question: we're trying to find the answer choice that "most seriously calls into question the explanation given for the thrush’s diet during migration." So, we don't need an option that utterly destroys the explanation -- we just need one that calls it into question more than the other options do.

(C) does exactly that: by even raising the issue of net calories, it casts some doubt on the nutrient-based explanation. Perhaps, on balance, birds actually get more calories from eating berries than from eating insects. You're right that we don't know this for sure without additional info -- but it does provide us a reason to question the author's explanation. None of the other answer choices do that, so (C) is the correct answer.

I hope that helps!
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Re: Most of the year, the hermit thrush, a North American songbird, eats [#permalink] Most of the year, the hermit thrush, a North American songbird, eats   15 Aug 2024, 23:35
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WillGetIt wrote:
Most of the year, the hermit thrush, a North American songbird, eats a diet consisting mainly of insects, but in autumn, as the thrushes migrate to their Central and South American wintering grounds, they feed almost exclusively on wild berries. Wild berries, however, are not as rich in calories as insects, yet thrushes need to consume plenty of calories in order to complete their migration. One possible explanation is that berries contain other nutrients that thrushes need for migration and that insects lack.

Which of the following, if true, most seriously calls into question the explanation given for the thrush’s diet during migration?

(A) Hermit thrushes, if undernourished, are unable to complete their autumn migration before the onset of winter.

(B) Insect species contain certain nutrients that are not found in wild berries.

(C) For songbirds, catching insects requires the expenditure of significantly more calories than eating wild berries does.

(D) Along the hermit thrushes’ migration routes, insects are abundant throughout the migration season.

(E) There are some species of wild berries that hermit thrushes generally do not eat, even though these berry species are exceptionally rich in calories.

Fact: Most of the year, the hermit thrush, eats a diet consisting mainly of insects. Except in autumn when they feed almost exclusively on wild berries.
Problem: wild berries contains less calories than insects and birds need a lot of calories to complete their migration.
Potential explanation: berries contain other nutrients that thrushes need for migration and that insects lack

What am I asked ? => Find the answer that weaken most the explanation.

(C) For songbirds, catching insects requires the expenditure of significantly more calories than eating wild berries does.

If birds expend more calories catching the insects than eating wild berries, then they have no reason to eat insects even if they contain more calories.
=> New explanation for the thrush’s diet during migration => Weaken the other one
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Re: Most of the year, the hermit thrush, a North American songbird, eats [#permalink]
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