Some members of this phylum keep their bodies clean through the use of pedicellaria
(pe-deh-sell-AIR-ee-uh). Its species have a system of interlocking calcium carbonate plates calledstereom. Many members of this phylum exhibit (*) pentaradial symmetry, and have tube feet calledpodia. Podia are found at the end of this phylum's main method of movement and respiration, the water-vascular system. Name this phylum of sea cucumbers and starfish, which has a Greek name that describe its members' spiny skin.

Definitely is  ECHINODERMATA

Explanation:

Echinoderms are marine invertebrates characterized by radial symmetry, they are animals that have 5 or more arms. This phylum includes, among others species, sea urchins,  sea cucumbers, brittle stars, starfish, crinoids  and sand dollars

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).

the answer is c.mitochondria. glad to .