There are seven classes of vertebrates. Sharks have a cartilage skeleton. Ninety five percent of all fish are in the class agnatha. No amphibians have claws on their toes. The tail of a salamander is flattened from top to bottom.
Reptiles have a two-chambered heart.
The membrane lining the shell of an amniote egg is known as the glottis. Hemotoxins are proteins that destroy red blood cells and disrupt blood clotting. The ventral shell of a turtle is known as the carapace. Enamel is a hard, smooth covering protecting the crown of a tooth. Incisors are shaped for puncturing and tearing.