Passage Summary: Biologists are arguing about how flight started. One group thinks it began with sea reptiles because feathers look like scales. Another group says that's wrong because bats fly without scales and plenty of land reptiles have scales too. A third group thinks flight started with tree-climbing reptiles jumping between branches.

Conclusion: The theory that flight originated in marine reptiles is incorrect.

Reasoning: The argument points out that bats lack scales and that nonmarine reptiles possess scales, suggesting that the presence of scales is not a unique or sufficient indicator of the evolutionary path toward flight.

Analysis: In this 'Role in Argument' question, we need to see how the specific claim about nonmarine reptiles fits into the structure. The claim is used by the second group of biologists to undermine the evidence offered by the first group. By showing that nonmarine reptiles also have scales, they demonstrate that having scales doesn't necessarily mean a creature is on the path to developing flight. It serves as a premise that supports the rejection of the marine-origin hypothesis.