An animal with bilateral symmetry a. has left and right sides. b. usually displays cephalization. c. produces mirror images regardless of the number of “cuts” trough the central axis. d. has left and right sides and usually displays cephalization. e. has left and right sides, usually displays cephalization, and produces mirror images regardless of the number of “cuts” trough the central axis.

organisms that lack symmetry are called asymmetrical and belong to phylum porifera/sponges.

organisms with specialized stinging cells belong to phylum cnidaria. stinging cells are called cnidoblast cells.

cnidarians show two morphological forms : polyp (sessile) and medusa (mobile)

filter feeding is observed in porifera members.  

alternation of generation is observed in coelenterata or cnidaria. there is alternation of asexual polyp form and sexual medusoid form. it is also referred as metagenesis.