... for more < /b> Ihan 100,000,000 years. Some of the reptiles developed feathers on their bodies, and their forelimbs became wings. In time they learned to fly, and birds came into being. Birds' ... pairs of ribs attached to that very flexible backbone. Ball-and-socket joints attach the sections of the backbone to one another, and each rib to a section of the backbone. So great ... and ringed birds returning have been recorded passing the same locality on the same date in consecutive years. Birds are able to navigate by means of the sun and stars, but how they...