Question

which organisms are considered parazoa?
cnidaria
bilateria
porifera

Explanation:

Parazoa is a taxon at the base of the phylogenetic tree of the animal kingdom. Sponges (Porifera) are considered Parazoa because they lack true tissues and organs and have a relatively simple body plan compared to more complex animals. Cnidaria have true tissues (ectoderm, endoderm, and in some cases mesoglea) and are part of Eumetazoa. Bilateria is a major group of animals with bilateral symmetry and three germ layers (ectoderm, mesoderm, endoderm), also within Eumetazoa.

Answer:

Porifera