This document discusses the life cycles of different animals. It explains that some animals, like many insects and amphibians, undergo a complete metamorphosis where they hatch from eggs as larvae that look different from adults and later form cocoons to transform into adults. Other animals, including mammals, birds, reptiles and some insects, experience an incomplete metamorphosis where young that hatch from eggs more closely resemble adults and transition to adulthood by shedding skins rather than forming cocoons.