Question

Which of the following characters represent flight adaptation of birds?

• A. Bones are pneumatic.
• B. Sternum has keel for attachment of flight muscles.
• C. Forelimbs are modified into wings.
• D. All of the above.

Answer 1

The correct option is D All of the above.

The presence of feathers is the most distinguishing feature of all birds. Feathers are highly modified scales that help the wings generate thrust and lift. They also streamline the body to reduce drag as the bird travels through the air. Since the bird bones are hollow (pneumatic bones), they also reduce weight. Birds have keeled sternum bones for the attachment of enormous muscles that power their wings, and a special bone called as the semilunate carpal that allows them to flap their wings efficiently. All birds have a special system of airways throughout their skeletons and a four-chambered heart. These organ systems provide the flight muscles with a steady supply of oxygen-rich blood that prevent their wings from becoming exhausted while the bird is in the air.