During the month of May, crabs arrive on Delaware's beaches to lay egg

Question

During the month of May, crabs arrive on Delaware's beaches to lay eggs. Certain shorebirds depend on these eggs for food during their annual spring migration to their northern breeding grounds. Delaware's crab population has declined recently. This decline, however, poses no serious threat to the migrating shorebird populations: by remaining longer in Delaware, the birds will be able to eat enough crab eggs to allow them to complete their migration.

Which of the following, if true, most seriously weakens the argument?

(A) No other food available to the birds on Delaware's beaches is as nutritious and accessible as are crab eggs.

(B) The decline in the number of crabs on Delaware's beaches is due to the harvesting of crabs by humans.

(C) There are more crabs on Delaware's beaches than in any other area that the migrating birds pass through.

(D) The crabs do not conceal their eggs.

(E) The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully.

mejia401 · Accepted Answer

Conclusion: This decline, however, poses no serious threat to the  migrating shorebird populations: 
Premise: ...by remaining longer in Delaware, the birds will be able to eat enough crab eggs to allow them to complete their migration.

Reasoning:   This is a causal relationship between "eating enough crab eggs" and "migrating shorebird populations". The cause is "eating enough crab eggs," and the effect is"migrating shorebirds populations." Additionally, there is another, embedded relationship: "by remaining longer" and "be able to eat enough crab eggs" and "successfully breed." A->B->C

Thus, the conclusion can be weakened if (1) an alternative cause is proposed; (2) cause occurs and the effect does not occur; (3) cause does not occur and the effect does; (4) the relationship is reversed; (5) the validity of the data is weakened.

A. No other food available to the birds on Delaware's beaches is as nutritious and accessible as are crab eggs.  Neutral. No change to the cause or effect whatsoever.

B. The decline in the number of crabs on Delaware's beaches is due to the harvesting of crabs by humans.  Shell game. Whether or not the crabs are declining because of humans, the length of the stay of shorebirds does not affect the shorebirds populations.

C. There are more crabs on Delaware's beaches than in any other area that the migrating birds pass through.  Neutral. Whether or not there are more crabs on the beach than migrating birds, the length of the stay of shorebirds does not affect the shorebirds populations

D. The crabs do not conceal their eggs.  Out of scope. No affect on conclusion.

E. The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully.  OK - The length of time does matter in how successful their breeding is. If the birds stay longer than normal, then the migrating shorebird populations could be affected. Thus, the cause of "remaining longer in Delaware" occurs, but the effect "shorebird populations" does not occur.

IMO E

GMATNinja · Answer

We are told that the crab population has declined recently, so the concern is that there will be less food (crab eggs) for the migrating birds. The author argues that the population decline "poses no serious threat to the migrating shorebird populations" because the birds can simply remain longer in Delaware while they "fuel up" on crab eggs. In other words, the author says that the birds won't have a problem getting the amount of food they need eventually. The birds will simply have to stay in Delaware a bit longer to get the amount of food they need. According to the author, this extra time spent in Delaware is not a problem.

Choice (E) tells us that spending extra time in Delaware IS a problem. If the birds stay in Delaware longer, they will complete their migration later. If they complete their migration later, they will be LESS likely to breed successfully. So the decline in the crab population DOES pose a serious threat "to the migrating shorebird populations." And (E) is correct.

I hope that helps!

xALIx · Answer

Between E and A. E is my pick. 
E shows that the conclusion reached by the stem is weakend given this additional information.
A on the other hand is somewhat off topic and doesn't directly affect the conclusion/argument as much.
Just my 0.02

chicagocubsrule · Answer

For weakening questions you should focus primarily on the conclusion ("this decline, however, poses no serious threat to the migrating shorebird populations:"). The correct answer should discredit or show that the conclusion is not likely
A - Other food? Not relevant
B - What caused the decline is not relevant.
C - Any other area? We are only concerned with Delaware
D - Whether the eggs are concealed or not is not an issue
E - This shows that the delay may result in some type of serious threat. So this is the credited response.

unplugged · Answer

Agree with E A is wrong also because it is a general statement about "birds" The argument is about certain shorebirds Lots of people getting 'lured...' :wink:

Cheers, Unplugged

semwal · Answer

PREMISE 1. During the month of May, crabs arrive on Delaware's beaches to lay eggs. Certain shorebirds depend on these eggs for food during their annual spring migration to their northern breeding grounds. 
PREMISE 2. Delaware's crab population has declined recently. 
PREMISE 3. By remaining longer in Delaware, the birds will be able to eat enough crab eggs to allow them to complete their migration. 
CONCLUSION- This decline poses no serious threat to the migrating shorebird populations.

Which of the following, if true, most seriously weakens the argument?

A. No other food available to the birds on Delaware's beaches is as nutritious and accessible as are crab eggs. NUTRITIOUS IS NOT THE ISSUE..WHETHER decline poses serious threat to the migrating shorebird populations IS THE ISSUE .  
B. The decline in the number of crabs on Delaware's beaches is due to the harvesting of crabs by humans. CAUSE FOR DECLINE IN CRABS IS NOT THE ISSUE....WHETHER decline poses serious threat to the migrating shorebird populations IS THE ISSUE.  
C. There are more crabs on Delaware's beaches than in any other area that the migrating birds pass through. WE ARE NOT CONCERNED WITH OTHER BEACHES..WHETHER decline poses serious threat to the migrating shorebird populations IS THE ISSUE..  
D. The crabs do not conceal their eggs... IRRELEVANT.WHETHER decline poses serious threat to the migrating shorebird populations IS THE ISSUE  
E. The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully.... CORRECT....Decline WILL pose serious threat to the migrating shorebird populations AS THE BIRDS WILL STAY LONGER TO EAT THE EGGS LEADING TO INSUFFICIENT breedING HENCE REDUCTION IN POPULATION... .

getbetter · Answer

For weaken questions target the assumption. You can target the conclusion also but that should be secondary I feel.

A causes B.

A = assumption = by remaining longer in Delaware, the birds will be able to eat enough crab eggs to allow them to complete their migration
B = conclusion = decline, however, poses no serious threat to the migrating shorebird populations

How to weaken : Find a answer that will not make the bird stay longer. (not enough eggs already mentioned so we're not picking this point)
 E-answer

ajay2121988 · Answer

I don't agree with your viewpoint. When the option says 'the birds', it's logically referring to the shorebirds.

Issue with A is that nutritious value and accessibility of eggs are not the issues at hand here.
Let's walk through the argument.

Imagine a nice, beautiful sea shore. Come May and I see a lot of crabs coming down to the shoreline but hey! what are they doing here ?
I see, they are laying lots and lots of eggs. Ok.
I also see certain birds coming here and feeding on these eggs. People tell me (the argument tells me) that these are migratory birds and they depend on these eggs for food in order to complete their annual migration. Seems these birds actually live somewhere else but migrate in order to breed. On the way they stop on this shore to have eggs. Hmm. Ok.
Now, some change has happened. The crab population has declined, I see. So that may mean fewer eggs, or maybe not, if the existing crabs lay more eggs. Let's see.
But people tell me that this decline will not harm the birds. Well, why ? Because the birds can stay longer and have their fill before leaving.

Alright. So to compensate for the fewer eggs available, birds can stay longer on the shore, have similar quantity of eggs as they used to before the population decline and continue flying toward their destinations.
Essentially, the birds are compromising time for food. Looks like even if they spend a lot of time on the shore, it won't matter to them. It seems eating the right quantity of eggs is really important for these birds compared to the time.

Now, that I can see though the argument, let me think of weakeners. Something that tells me that this is not the right strategy for the birds. Something that tells me that by waiting for the eggs, they will not succeed. Enough thinking. Let's dive into the options.

A> This says crab eggs are the most nutritious and accessible food available to the birds. Well, ok, but how does this affect the strategy that the birds are going to deploy in order to ensure that the decline in the crab population and the subsequent decline in the number of eggs does not affect them ? Not related to issue at hand.

B> The decline is due to harvesting by humans, or due to pollution or due to Trump winning US elections. Why the decline is happening is not our issue. Eliminated.

C> O wow! There are more crabs on Delaware's beaches than in any other area the birds pass through. So ? Aren't we concerned about the population decline on Delaware beaches only ? This option unnecessarily brings other beaches into picture. Not ok.

D> Crabs don't conceal their eggs. Alright. They did not conceal before the decline, they don't conceal now. How does this affect the birds strategy ?

E> Earlier the birds complete their migration, better are the chances that they breed successfully. Ok. Interesting thing about this option is that it hits the bird's strategy.
 So it's definitely relevant, first of all. Now, this option tells us that time IS an important factor for the birds. They cannot chose to spend time waiting on the beautiful 
 Delaware beaches for eggs. This option tells us that hey! the birds can't really laze around the beach ! They got work to do ! They got to reach their destination on time! 
 Otherwise they may not breed successfully. Looks ok and better than all other choices.

E it is.

gmatexam439 · Answer

During the month of May, crabs arrive on Delaware's beaches to lay eggs. Certain shorebirds depend on these eggs for food during their annual spring migration to their northern breeding grounds. Delaware's crab population has declined recently.  This decline, however, poses no serious threat to the migrating shorebird populations : by remaining longer in Delaware, the birds will be able to eat enough crab eggs to allow them to complete their migration.

Which of the following, if true, most seriously weakens the argument?

A. No other food available to the birds on Delaware's beaches is as nutritious and accessible as are crab eggs. - Okay, so as per the argument shorebirds will stay for longer time on the beach and continue on their journey. This has no impact on the argument. 
B. The decline in the number of crabs on Delaware's beaches is due to the harvesting of crabs by humans. - We are concerned about the population of shorebird 
C. There are more crabs on Delaware's beaches than in any other area that the migrating birds pass through. - This strengthens the argument because it states that birds will stop at that beach only. 
D. The crabs do not conceal their eggs. - This is just a fact statement. 
E. The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully. - Correct. Highlighted part is the conclusion. This might impact the population of birds

Psk13 · Answer

GMATNinja   chetan2u 
please explain why the answer is E

HG0815 · Answer

IMO OA is E
Below is my reasoning.

A. No other food available to the birds on Delaware's beaches is as nutritious and accessible as are crab eggs. 
 -> Out of scope. We do not need to think about nutrition of food.
B. The decline in the number of crabs on Delaware's beaches is due to the harvesting of crabs by humans.
 -> Out of scope. We do not need to think about harvesting of crabs by human 
C. There are more crabs on Delaware's beaches than in any other area that the migrating birds pass through. 
 -> Not weeken. I think it can be strengthen.
D. The crabs do not conceal their eggs. 
 -> Nothing.
E. The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully.
 -> Correct
 The last sentence of passage argues that there is no threat to population.
 However, if E is correct, there would be serious threat to their population. So E is correct.

Aman1012 · Answer

looking for some easy explanation for option E

GMATNinjaTwo · Answer

Have you tried reviewing  this post ?

IloveMBA123 · Answer

Why B is incorrect and E is correcT?

B - If the decline is due to the harvesting, then the birds might not be able eat crab eggs at all (farmers will intervene whenever these birds try to eat the egg).

Therefore "by remaining longer in Delaware, the birds will be able to eat enough crab eggs to allow them to complete their migration."

The conclusion will fail because these birds will never get the chance to eat crab egg.

E - The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully. Ok, let's assume completing their migration latter in the season, those bird are not able to breed successfully. Ok... so there is still a chance to breed successfully right?

Answer B- 100 birds, zero foods, death rate = 100%; Population drop from 100 to 0
Answer E- 100 birds, 100 Foods, death rate = 0 %; fertility rate decrease from 100% to 30%, = they are still able to breed 30 birds population from 100 to 130

Can someone help please?

Mayankcadbury · Answer

VeritasKarishma  Need your help. Why OPTION A is not the right answer

KarishmaB · Answer

In May, crabs arrive on Delaware's beaches to lay eggs. 
Certain shorebirds depend on these eggs for food during their annual spring migration to their northern breeding grounds. 
Delaware's crab population has declined recently. 
By remaining longer in Delaware, the birds will be able to eat enough crab eggs to allow them to complete their migration.

Conclusion: This decline poses no serious threat to the migrating shorebird populations.

The issue is that some shorebird depend on crab eggs and crab population has gone down. The argument says that the birds can stay longer (so they will get enough eggs). Hence, the argument concludes that the decline in crab population is not a threat to these birds.

We need to weaken the argument. How can we do that? If we say that the birds will not be able to stay longer, that will weaken the argument.

(A) No other food available to the birds on Delaware's beaches is as nutritious and accessible as are crab eggs.

The argument is not relying on other food sources. It is saying that the birds will consume these eggs only. Just that they will stay longer to consume enough eggs. This doesn't weaken our argument.

(B) The decline in the number of crabs on Delaware's beaches is due to the harvesting of crabs by humans.

Irrelevant why the number of crabs has reduced.

(C) There are more crabs on Delaware's beaches than in any other area that the migrating birds pass through.

Irrelevant. We already know that the birds depend on crabs in Delaware.

(D) The crabs do not conceal their eggs.

Irrelevant.

(E) The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully.

Correct. This tells us that the birds will not be able to stay longer. If they will stay longer, they may not be able to breed successfully. Then there is a threat to the birds due to decline in crab population.

Answer (E)

Mayankcadbury · Answer

Thanks for the wonderful explanation

NandishSS · Answer

HI  mira93 ,  nightblade354 ,  eakabuah

Please add the tag as GMATPrep EP1.

I'm not sure why tags are missing

Bunuel · Answer

Done. Thank you.

P.S. We don't have GMATPrep EP1 tag anymore. Just GMAT Prep.

During the month of May, crabs arrive on Delaware's beaches to lay egg

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During the month of May, crabs arrive on Delaware's beaches to lay egg

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