Tadpole
After some time, the tadpoles begin to grow legs: first the hind legs and then the front legs. Then they are called froglets.  Soon after, froglets grow lungs and begin to breathe air and lose their tails.  The tail disappears because the cells in the tail gently die.  Each tadpole's mouth changes from small to as wide as its head.  Its intestines become shorter.  They grow larger, and eventually become adults.