Why were echinoderms able to inhabit all the seas and oceans in the depths and shallow waters?

Echinoderms are marine invertebrates that are found in all oceans of the world and at all depths. There are no echinoderms in freshwater environments. The presence of needles allows them to inhabit any depths. Echinoderms include many easily recognizable creatures such as starfish, sea urchins, sea cucumbers, and sea lilies. All of these animals have radial or biradial symmetry, and they fill many niches in marine environments as particle feeders, scavengers, and predators. The aquatic vascular system assists echinoderms in feeding, locomotion, and respiration.