Biological Classification - Echinodermata & Arthropoda

The video tutorial explores two major animal phyla: Echinodermata and Arthropoda. Echinoderms, such as starfish and sea urchins, are marine animals known for their radial symmetry, spiny skin, and ability to regenerate limbs. They possess a unique water-vascular system aiding in movement and feeding. Arthropods, including insects and crustaceans, are characterized by jointed appendages, segmented bodies, and chitinous exoskeletons. This phylum is the most diverse, comprising over 80% of described animal species.

What is a distinctive feature of the water-vascular system in echinoderms?

Describe the characteristics that define members of the Phylum arthropoda.