Question

All the following statements are correct about Aves but one is wrong. Which one is wrong?

• A. Fertilisation is internal
• B. They are oviparous and development is direct without exception
• C. They are homeothermal animals
• D. All the flightless birds have sternum with keel

Answer 1

The correct option is D All the flightless birds have sternum with keel

The characteristic features of Aves (birds) are the presence of feathers and most of them can fly except flightless birds (e.g., ostrich). They possess beak. The forelimbs are modified into wings. The hind limbs generally have scales and are modified for walking, swimming or clasping the tree branches. Endoskeleton is fully ossified (bony) and the long bones are hollow with air cavities (pneumatic). They have sternum with keel, but some flightless birds lack keel. They are warm-blooded (homiothermous) animals. Sexes are separate. Fertilisation is internal. They are oviparous. Development is direct.