Write a paragraph about birds?
Birds are warm-blooded flying vertebrates that have more than 10,400 species belonging to the Aves class. They have two eyes, a four-chambered heart shaped into feathery wings like human beings’ and forelimbs. For flying purposes, birds use their forelimbs and hind limbs for resting or perching. Hard shelled eggs that require warm conditions to hatch are released by birds.
There are about 1000 extinct bird species identified from fossils, even with such numerous species. All birds produce a single egg, incubate, grow and later enter the adult bird population with such a wide range of species. During their life cycle, some birds also migrate.