2 1.1.4 Quiz: Working in Science Question 6 of 10
When the theory that the Sun goes around Earth was replaced with the theory
that Earth goes around the Sun, this was an example of a

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.

is this a psat question, if so do not cheat try your best.