medium · LSAT Logical Reasoning
Ecologist: For decades the riverbank ecosystem in this valley had no wolves, its elk herd grew enormous, and the elk overgrazed the willows and aspens along the streams. Several years after wolves were reintroduced, the elk population dropped to roughly its historical size and the streamside vegetation returned to its former abundance. The reintroduction of wolves has therefore restored the ecosystem's balance.
Which one of the following principles, if valid, most helps to justify the ecologist's reasoning?
- When the return of a native predator brings an ecosystem's prey numbers and vegetation back to their historically typical levels, that ecosystem counts as restored.
- An ecosystem cannot recover its vegetation in the absence of a top-level predator such as the wolf.
- Wolves ought to be reintroduced to every national park in which they were once native.
- Predators are the single most important factor in maintaining the health of any riverbank ecosystem.
- Once an ecosystem has been disrupted, no intervention can ever fully return it to its original condition.
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More LSAT Logical Reasoning practice
- Which one of the following is an assumption required by the argument?
- Which one of the following can be properly inferred from the statements above?
- The question type just described is best identified as which one of the following?
- The reasoning in the argument is flawed in that the argument
- The reasoning in the argument is flawed because the argument
- Which one of the following most accurately describes the relationship the statement establ
- Which one of the following can be validly inferred from the two conditionals above?
- Which one of the following must be true given the statement above?