Whats so special about water vascular system of echinodermata that makes it a distinctive feature of an echinoderm ????

Dear Student, In water vascular system of echinoderms, water moves through central and radial canals and helps the organisms in locomotion, exchange of gases, Transport of nutritious materials and also to predate other organisms. This is seen in echinoderms only and that's why it is characteristic feature. Regards