Animal Diversity 7th Edition by Cleveland Hickman,Larry Roberts,Susan Keen ,Allan Larson,David Eisenhour

Exercise 2

The special adaptations of birds contribute to two essentials for flight: more power and less weight. Explain how each of the following contributes to one or both of these two essentials: feathers, skeleton, muscle distribution, digestive system, circulatory system, respiratory system, excretory system, reproductive system.