Many animals can be categorized as either protostomes and deuterostomes based on certain features of their embryonic development. Determine whether each of the following terms applies to only protostomes, only deuterostomes, both protostomes and deuterostomes, or neither. The items are spiral determinate cleavage, coelom from solid masses of mesoderm, anus from blastopore, coelom from folds of archenteron, radial intermediate cleavage, mouth from blastopore, diploblast, and triploblast.

The major distinctions between these two groups of animals (Bilateria) deuterostomes and protostomes are in their embryonic development. Another difference is that most Protostomes have schizocoelous development (cells fill in the interior of the gastrula and that is the way the mesoderm is formed) On the other side, in Deuterostomes, the mesoderm forms through invagination of the endoderm (enterocoelic pouching).

Some of the animals that belong to Protostomes are arthropods, nematodes, molluscs, annelids, platyhelminths. Some of the animals that belong to the Deuterostomes are Chordata, Echinodermata, Hemichordata.