Define the following terms:
$(i)$ Triploblastic
$(ii)$ Coelom

(N/A) $(i)$ Triploblastic: Animals in which the developing embryo has a third germinal layer,the mesoderm,present between the ectoderm and endoderm are called triploblastic animals. Examples include all animals from phylum Platyhelminthes to phylum Chordata.
$(ii)$ Coelom: The body cavity which is lined by mesoderm is called coelom. Animals possessing coelom are called coelomates (e.g.,Annelids,Molluscs,Arthropods,Echinoderms,Hemichordates,and Chordates).