SAT Reading & Writing · Command of Evidence (textual)
Killifish populations living in several heavily polluted American estuaries independently evolved tolerance to toxic industrial chemicals…
Killifish populations living in several heavily polluted American estuaries independently evolved tolerance to toxic industrial chemicals in their water. An op-ed argues that because these fish evolved tolerance, industrial pollution in waterways must not pose a serious ecological threat. Which finding would most directly undermine the op-ed's argument?
Answer and explanation
Answer: C: Tolerant killifish populations can carry biological tradeoffs from their adaptation, and the surrounding contaminated ecosystems continue to suffer damage regardless of one species' evolved tolerance.
The op-ed's leap is from "one species adapted" to "pollution isn't harmful," and C directly closes that gap by noting the adaptation carries its own costs and that the broader ecosystem remains damaged regardless of this one species' tolerance. A explains the genetic mechanism behind the adaptation without addressing overall ecological harm. B and D are background facts about the species and pollution history that don't speak to ecosystem-wide impact.
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