Characteristic features of class Aves (the birds)
General features: Birds are cosmopolitan and found in all continents, seas and most islands. Their wide occurrence is due to their power of flight, which […]
cloaca
Characteristic features of class Amphibia
Natural history: The amphibians (the vertebrates with dual life) were the first vertebrates to invade land, but they aren’t fully dependent to terrestrial life. They […]