Global surveys estimate the earth's population of nesting female leatherback turtles has fallen by more than two-thirds in the past 15 years. Any species whose population declines by more than two-thirds in 15 years is in leatherback turtle is clearly in danger of extinction.
What this question is testing
Your task
Find the assumption the argument requires in order for its conclusion to hold.
Common trap
Answers that would help the argument but aren't strictly required (sufficient, not necessary).
Winning move
Negate each choice — the right one breaks the argument when negated.
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