Necessary AssumptionDiff: Easy
Logic Breakdown
Passage Summary: The number of egg-laying female leatherback turtles has plummeted recently. Since any animal group that loses that many members so quickly is in trouble, these turtles are headed for extinction.
Conclusion: Leatherback turtles are currently at risk of going extinct.
Reasoning: The population of nesting females has dropped by more than two-thirds in 15 years, and any species with such a decline is considered in danger.
Analysis: The argument makes a leap from a decline in 'nesting females' to a decline in the 'species' as a whole. For the conclusion to hold, the decline in nesting females must accurately reflect a decline in the total population. If the total population stayed the same while only the nesting habits changed, the argument would fall apart, so look for an answer that connects the female count to the species count.
Conclusion: Leatherback turtles are currently at risk of going extinct.
Reasoning: The population of nesting females has dropped by more than two-thirds in 15 years, and any species with such a decline is considered in danger.
Analysis: The argument makes a leap from a decline in 'nesting females' to a decline in the 'species' as a whole. For the conclusion to hold, the decline in nesting females must accurately reflect a decline in the total population. If the total population stayed the same while only the nesting habits changed, the argument would fall apart, so look for an answer that connects the female count to the species count.
Passage Stimulus
Passage Redacted
Unlock Full Passage9.Which one of the following is an assumption that the argument requires?
Correct Answer
A
A is necessary because it links the subset to the whole. If the decline in nesting females is proportional to (i.e., tracks) the decline in the entire species, the species has indeed fallen by >2/3 and the principle applies. Negation test: If the decline in nesting females is not proportional to the decline in the species as a whole, then a >2/3 drop in nesting females could occur even if the total species population did not drop by >2/3. In that case, the principle would not justify the conclusion, undermining the argument. Thus A is required.
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