Acertain igneous rock contains about 75 percent dark silicate minerals. the remainder of the rock is mostly plagioclase feldspar. what type of composition does this igneous rock have?

answer; /// i believe that the correct answer is; ///a combination of the birth and death

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.