The structures of the endocrine system are crucial to performing functions that are essential in life processes. what is the major function performed by the endocrine system? a. it affects the reproductive system. b. it releases hormones into the bloodstream. c. it competes with the nervous system. d. it is made up primarily of glands with ducts.

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.