Which statement about animal nervous systems is true? Group of answer choices All taxonomic groups of animals have nervous systems, except annelids. All taxonomic groups of animals have nervous systems, except sponges and jellyfish All taxonomic groups of animals have nervous systems, except jellyfish. All taxonomic groups of animals have nervous systems, except sponges

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.

more words for this could be abiotic and biotic

abiotic: living organisms within an ecosystem

biotic: non-living organisms within an ecosystem