Birds are thought to have evolved from small feathered dinosaurs. Evidence for this comes from the fossil discoveries of , a transitional form between dinosaurs and birds.

Archaeopteryx

Explanation: The Archaeopteryx is known as the transitional form between dinosaurs and birds. Archaeopteryx had features that links it to present-day reptiles and birds. It had feathered wings but a bony tail, and is believed to have evolved into birds in 10 million years.  

The Archaeopteryx had a flat sternum, unlike modern day birds. Birds which fly have a keeled sternum and it is possible that the Archaeopteryx did not use sustained flight as a method of movement and the feathers were mostly a means of insulation.  

answer; the correct answer is (composition);

well 1 they have there leader that controls them