During the month of May, crabs arrive on Delaware's beaches to lay eggs. Certain shorebirds depend on these eggs for...
GMAT Critical Reasoning : (CR) Questions
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?
Passage Analysis:
| Text from Passage | Analysis |
| During the month of May, crabs arrive on Delaware's beaches to lay eggs. |
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| Certain shorebirds depend on these eggs for food during their annual spring migration to their northern breeding grounds. |
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| Delaware's crab population has declined recently. |
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| 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. |
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Argument Flow:
The argument starts by explaining a natural relationship - crabs lay eggs, birds eat those eggs during migration. Then it presents a potential problem (declining crab population) but immediately dismisses this concern with a proposed solution (birds staying longer).
Main Conclusion:
The decline in Delaware's crab population poses no serious threat to migrating shorebird populations.
Logical Structure:
The author acknowledges that fewer crabs means fewer eggs available, but argues that birds can compensate by extending their stay in Delaware. The logic assumes that staying longer will allow birds to collect the same total amount of food they need, just spread over more time.
Prethinking:
Question type:
Weaken - We need to find information that would reduce our belief in the conclusion that birds will be fine despite fewer crabs because they can just stay longer in Delaware
Precision of Claims
The argument makes specific claims about bird behavior (staying longer), timing (during migration), and outcomes (getting enough eggs to complete migration). We need to target these precise elements
Strategy
Look for scenarios that show why staying longer in Delaware won't actually solve the birds' problem. Focus on what could prevent the 'stay longer = get enough eggs' solution from working, while accepting the facts that crabs have declined and birds do depend on these eggs
'No other food available to the birds on Delaware's beaches is as nutritious and accessible as are crab eggs.' This actually strengthens rather than weakens the argument. If crab eggs are the best food source available, this supports the idea that birds should indeed stay longer in Delaware to get more of these optimal eggs rather than leaving for inferior food sources elsewhere. This doesn't challenge the conclusion that staying longer will solve the problem.
'The decline in the number of crabs on Delaware's beaches is due to the harvesting of crabs by humans.' While this explains the cause of the crab decline, it doesn't affect whether the proposed solution (staying longer) will work. The argument doesn't depend on why crabs declined - only on whether birds can compensate by extending their stay. The cause is irrelevant to evaluating the effectiveness of the proposed solution.
'There are more crabs on Delaware's beaches than in any other area that the migrating birds pass through.' This actually supports the argument's conclusion. If Delaware has the highest concentration of crabs along the migration route, this reinforces that staying longer in Delaware (rather than moving on) is indeed the best strategy for the birds to gather sufficient eggs.
'The crabs do not conceal their eggs.' This information is neutral to the argument. Whether eggs are hidden or visible doesn't impact the core logic about whether staying longer will allow birds to collect enough eggs. The accessibility of eggs doesn't change whether the compensation strategy will work.
'The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully.' This seriously weakens the argument by revealing a critical flaw in the proposed solution. If staying longer in Delaware delays migration completion, and later completion reduces breeding success, then the 'solution' creates a new serious problem. Birds face a dilemma: leave with insufficient food or stay longer but risk breeding failure. Either way, the crab decline poses a serious threat, contradicting the main conclusion.