GRE Reading Comprehension: Maggoosh-GRE阅读Maggoosh - M1W4LUZ0Z75JH4XWM

In the highlighted sentence the author implies that A. most flying dinosaurs underwent similar transformations B. only a theory that accounts for the scarcity of resources can account for the physiological adaptations of the Pteranodon C. dinosaurs only underwent evolutionary change if doing so provided an obvious advantage D. the Pteranodon had originally only been able to walk before evolving the ability to fly E. the Pteranodon would be able to access sufficient food while in flight