Amphibians
Amphibia (Amphibia) includes all the eggs without egg shells, vertebrates with limbs. Amphibian skin exposed, the surface is not scaly, hair and other coverage, but can secrete mucus to keep the body moist; its larvae live in the water, with gills breathing, grow up with lung and skin breathing. Amphibians can climb the land, but can not live away from the water, because it can survive in two places, known as amphibious. It is the transitional type of vertebrate from aquatic to terrestrial. There are now more than 3,000 kinds of amphibians. Amphibians are cold-blooded animals. ...