Recently discovered fossil evidence casts doubt on the evolutionary theory that dinosaurs are more closely related to reptiles than to other classes of animals.
Conclusion
New fossil evidence casts doubt on the theory that dinosaurs are more closely related to reptiles than to other classes of animals.
Evidence
Some dinosaurs had hollow bones, found today only in warm-blooded creatures such as birds.
Dinosaurs had well-developed sight and hearing, unlike present-day cold-blooded reptiles.
Some dinosaurs had arched mouth roofs that allowed breathing while eating, as fast-breathing animals such as birds need; all fast-breathing animals today are warm-blooded.
Many dinosaurs grew in a pattern typical of warm-blooded animals.
Evaluate
The stem asks how the argument proceeds, so the job is to name the move. Every piece of evidence has the same shape: here is a dinosaur feature, and here is which living group has it. Hollow bones, keen senses, breathing while eating, growth pattern. In each case the feature matches warm-blooded animals, birds in particular, and not reptiles.
So the method is comparison by traits. The author lines up a creature from the past against two groups alive today and shows, trait by trait, that it resembles one group more than the other. That resemblance is what undermines the reptile theory. The author does not state a general rule and apply it, does not accuse the old theory of resting on false data, and does not reason about the present at all. The conclusion is about dinosaurs.
Goal
Find the answer that describes a trait-by-trait comparison showing a past creature is more like one present-day group than another.