Question

what are the criterias for metamerization????????

Answer 1

In the annelids, arthropods, and chordates there is a linear repetition of body parts known as segmentation (metamerism); each repeated unit is a somite (metamere). In earth-worms the successive somites are essentially alike, but they are unlike in different body regions of a crayfish or insect. Metamerism is conspicuous both externally and internally in annelids, is mostly external with arthropods, and mainly internal in man and other chordates (vertebrae, body muscles, some blood vessels, and nerves).