Networks of blood vessels in bats' wings serve only to disperse heat generated in flight. This heat is generated
only because bats flap their wings. Thus paleontologists' recent discovery that the winged dinosaur Sandactylus
had similar networks of blood vessels in the skin of its wings provides evidence for the hypothesis that
Sandactylus flew by flapping its wings, not just by gliding.
In the passage, the author develops the argument by
(A) forming the hypothesis that best explains several apparently conflicting pieces of evidence
(B) reinterpreting evidence that had been used to support an earlier theory
(C) using an analogy with a known phenomenon to draw a conclusion about an unknown phenomenon
(D) speculating about how structures observed in present-day creatures might have developed from similar
structures in creatures now extinct
(E) pointing out differences in the physiological demands that flight makes on large, as opposed to small,
creatures