Diversity In Living Organisms — Science STD 9 — Question

Flight adaptations of the birds are the following:

1. Forelimbs are modified into wings.
2. Body is covered with exoskeleton of waterproof and lightweight feathers.
3. Long bones of endoskeleton are pneumatic having air cavities.
4. All birds are toothless; their jaws are modified into horny beaks.
5. Body is streamlined to reduce air resistance during its flight.
6. Birds have air sacs helping in double respiration.
7. Flight muscles are well developed.
8. Tail feathers form a steering apparatus.
9. Birds have an acute vision.