define metazoans and parazoans.

Dear student,,Metazoans include all the heterotrophic, eukaryotic and multicellular animals. In others words all multicellular animals are called metazoans. They include different phyla of animals like ​Porifera, Cindaria, Coelenterata, Platyhelminthes, Aschehelminthes, Nematoda, Annelida, Mollusca, Arthropoda, Echinodermata and Chordata. Metazoa are further divided into parazoa and eumetazoa based on complexity of body structure.In parazoans the cells are loosely aggregated and form tissues or organs, examples are sponges.