Question

Scientists discovered a fossil in China that belongs to a previously unknown species of an obscure group of small dinosaurs, related to primitive birds such as the famous Archaeopteryx. It had feathers, but they seemed too insubstantial to be useful in flight. Then the scientists said they recognized the unusually long, rod-like bone extending from each of the two wrists: curving structures possibly supporting an aerodynamic membrane. These scientists are grouping the found fossil with birds, based on ________ structures.

Answer 1

Answer:

Physical.

Explanation:

These scientists group the found fossil with birds on the basis of physical structures because first the scientists relate the fossil to the feathers of the bird and later the scientists relate it to the bone structure to determine the resemblance between the birds and the fossil of an obscure group of small dinosaurs so we can conclude that the scientists observe the found fossil on the basis of physiological characteristics of that fossil.