In some animals, the body is externally as well as internally divided into segments with a serial repetition of atleast some organs. This is called Metamerism. In simple words, metamerism is the condition of being constructed of a linear series of repeating parts. For example, in earthworm the body shows metamerism.

Metagenesis is the reproduction cycle of an organism alternating between sexual and asexual mode.

Metamorphosis is the process by which animals like insects, amphibians and a few aquatic animals, undergo extreme and rapid physical changes after birth.