Why Can Birds Fly?

Birds can fly because they have special Organs-wings. When birds flap their wings, an ascending air current pushes up their wings, making their bodies fly up. Birds have well-developed breast muscles, they can beat their wings endlessly, and the air holds birds' bodies forward and upward. Thus birds can fly in the sky.

Besides wings, birds' bodies have many other advantageous conditions. They are round in the front and sharp m the rear. When flying, birds have little air resistance. Feathers cover birds' whole bodies, and there are no teeth in birds' mouths. Bones are hollow and bodies are very light. They don't keep excrement and urine in the body, but excrete them at all times. All these provide favourable conditions for bird's flying.