Last visit was: 26 Apr 2026, 18:00 It is currently 26 Apr 2026, 18:00
Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
555-605 (Medium)|   Weaken|                                 
User avatar
ThatDudeKnows
Joined: 11 May 2022
Last visit: 27 Jun 2024
Posts: 1,070
Own Kudos:
1,030
 [1]
Given Kudos: 79
Expert
Expert reply
Posts: 1,070
Kudos: 1,030
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
jabhatta2
Joined: 15 Dec 2016
Last visit: 21 Apr 2023
Posts: 1,251
Own Kudos:
Given Kudos: 188
Posts: 1,251
Kudos: 328
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
GMATNinja
User avatar
GMAT Club Verbal Expert
Joined: 13 Aug 2009
Last visit: 24 Apr 2026
Posts: 7,391
Own Kudos:
70,818
 [2]
Given Kudos: 2,132
Status: GMAT/GRE/LSAT tutors
Location: United States (CO)
GMAT 1: 780 Q51 V46
GMAT 2: 800 Q51 V51
GRE 1: Q170 V170
GRE 2: Q170 V170
Products:
Expert
Expert reply
GMAT 2: 800 Q51 V51
GRE 1: Q170 V170
GRE 2: Q170 V170
Posts: 7,391
Kudos: 70,818
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
RishiRamdani
Joined: 29 Jun 2024
Last visit: 21 Nov 2025
Posts: 21
Own Kudos:
9
 [1]
Given Kudos: 7
Location: France
GMAT Focus 1: 645 Q85 V81 DI79
GPA: 3.5
WE:Securities Sales and Trading (Finance)
GMAT Focus 1: 645 Q85 V81 DI79
Posts: 21
Kudos: 9
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
WillGetIt
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
User avatar
bhavyagmat
Joined: 19 Oct 2024
Last visit: 19 Apr 2026
Posts: 20
Own Kudos:
6
 [1]
Given Kudos: 75
Location: India
GRE 1: Q162 V161
GPA: 2.96
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I could easily eliminate B,D,E.
It came down to A) and C).

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

So this option gives a new information - that if undernouirshed - thrushes wont be able to complete migration. If this is true which the question stems asks be assume then the idea that despite the less calories through wild berries - the thrushes are able to complete the migration as a result of other nutrients falls flat and questions the explananation given

Now one loophole i have is what is undernourished - should we assume to be less calories. I believe i can take the leap due to Martys lessons Even if not, let me first see what i am up against in the other options to warrant the leap

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

We know songbirds need high calories to migrate. If for wild berries low-calorie expenditure than insect then the fact that having low calorie works because other nutrients help in migration are in WB and not in insect-- → This actually strengthens the given explanation that low calroies are compensated by other nutrients. Not weaken.
ThatDudeKnows
WillGetIt
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
User avatar
Siddharth17
Joined: 04 Dec 2025
Last visit: 25 Apr 2026
Posts: 11
Given Kudos: 9
Location: India
GMAT 1: 670 Q60 V53
GPA: 8.02
GMAT 1: 670 Q60 V53
Posts: 11
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I made stupid mistake of just looking for maturation in the sentence. I ended up selecting B even though I was not completely sure of it as nutritions that insects contains and berries lack might not be even required by the birds. But as I had completely eliminated C (I didn't even read it entirely), ended up selecting B,
User avatar
vasu1104
Joined: 10 Feb 2023
Last visit: 26 Apr 2026
Posts: 395
Own Kudos:
Given Kudos: 664
Location: Canada
Products:
Posts: 395
Kudos: 237
Kudos
Add Kudos
Bookmarks
Bookmark this Post
most part of year, songbird eats diets consisting mainly of insects but in autumn during their migration they eat wild berries.
wild berries are not rich in calories as insects are but still they consume plenty of calories.
reason for it is that there are some other nutrients in berries that insects lack.

A this has no impact whatsoever on the reasoning so reject.
B but then why are they not eating it? we need to know that and not more additonal info about insects nutrition side.
C if it takes more energy to catch insaects than to berries then it make complete sense from songbird side to keep eating berries and not waste their energy. so this gives alternate cause on why they are persisting on eating berries and not because of nutrients available to them.
D then they should eat them but they are not. so this somewhat strengthen it.
E completelt irrelevant.


WillGetIt
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.

Thrush Migration

Step 1: Identify the Question

The words calls into question indicate that this is a Weaken the Argument question.

Step 2: Deconstruct the Argument

T: usually eat insects

But migrate eat berries even tho fewer cal

Ó Berries nec nutrients

Step 3: Pause and State the Goal

On Weaken questions, the correct answer makes the conclusion less likely to be valid. The conclusion in this argument is a possible explanation for the thrush’s feeding behavior. One way to weaken this conclusion is to provide an alternative reason for this behavior.

Step 4: Work from Wrong to Right

(A) This information explains why nutrition is important for the thrush during migration. It does not, however, address why the thrush eats berries instead of insects.

(B) This answer provides another reason it might be better for thrushes to eat insects (other specific nutrients). It does not provide an alternative reason as to why thrushes eat berries.

(C) CORRECT. This answer provides an alternative reason that thrushes might choose to eat berries instead of insects while migrating: They don’t want to expend extra energy catching the insects. Even though the berries contain fewer calories, the thrushes might actually have a net gain of calories since they don’t have to chase and capture the berries.

(D) If insects are very abundant along the migration route but the thrush still prefers berries, then the conclusion is more likely to be valid, not less.

(E) The argument states that thrushes do eat berries while migrating. The fact that they do not eat all types of berries does not influence the explanation as to why they eat some berries.
­
   1   2 
Moderators:
GMAT Club Verbal Expert
7391 posts
506 posts
361 posts