Researcher: Dinosaurs lack turbinates -- nasal cavity bone structures in warm-blooded species that minimize water loss during breathing. According to some paleobiologists, this implies that all dinosaurs were cold-blooded. These paleobiologists must be mistaken, however, for fossil records show that some dinosaur species lived in Australia and Alaska, where temperatures drop below freezing. Only warm-blooded animals could survive such temperatures. Which one of the following most accurately describes the role played in the researcher's argument by the claim that only warm-blooded animals could survive temperatures below freezing? ["It is presented as counterevidence to the paleobiologists' assertion that dinosaurs lack turbinates.", "It is presented as a potential counterexample to the argument's main conclusion.", "It is a premise offered in support of the argument's main conclusion.", "It is the argument's main conclusion."]