Echinoderms are not characterized by: A. Bisexual animals B. Absence of excretory system C. Usually external fertilization D. Indirect development with free swimming larva
Option A They are unisexual animal they all possess five-part radial symmetry around a central disk. Second, they all possess a very unique water vascular system (vascular system based on water). These unique characteristics distinguish echinoderms from other animals in the animal kingdom.
