Dinosaurs used feathers to fly.
a. true, flying dinosaurs sometimes reached the size of small airplanes
b. false, dinosaurs weren't coordinated enough to fly
c. true, feather are delicate but supported dinosaurs at heights up to 1,000 feet
d. false, dinosaur arms were too short to support flight

The answer is D.

Dinosaurs with feathers could not fly. This was because their arms were too short, and their bodies too fat. Some dinosaurs could fly (Pteradon, Quetz, etc.) but they did not use feathers, they had skin-like flaps between their arms that allowed flight.

Hope this helped. Good luck!