What are the modifications that are observed in birds that help them fly?

What are the modifications that are observed in birds that helop them fly?

How does the endoskeleton of birds help them to fly?

Which of the following features of birds help them to fly?

What are the differences between bird and flying lizard ?

Some dinosaurs had fathers althought they could not fly but birds have feathers that help them to fly. In the context of evolutin this means that