What effect would El Niño most likely have on organisms? El Niño would cause the extinction of an entire species.
El Niño would cause changes in the genetic makeup of organisms.
El Niño would cause continents to move to different parts of the planet.
El Niño would cause organisms to move in search of food and better conditions.

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.

answer; the above answer to the above statement is (true)