The water vascular system of echinoderms a. functions as a circulatory system that distributes nutrients to body cells b. functions in locomotion and feeding. c. is bilateral in organization, even though the adult animal is not bilaterally symmetrical. d. moves water through the animal's body during filter feeding.

Verified step by step guidance

1. Understand the structure and function of the water vascular system in echinoderms: The water vascular system is a network of fluid-filled canals unique to echinoderms, such as starfish and sea urchins. It is primarily involved in locomotion, feeding, and respiration.
2. Evaluate option (a): This option suggests that the water vascular system functions as a circulatory system distributing nutrients. However, in echinoderms, this system is not involved in nutrient distribution, which is handled by the hemal system.
3. Evaluate option (b): This option is correct as the water vascular system in echinoderms indeed functions in locomotion and feeding. Tube feet, part of this system, help in movement and capturing food.
4. Evaluate option (c): This option states the system is bilaterally organized, which is incorrect. The water vascular system mirrors the radial symmetry of echinoderms, not bilateral symmetry.
5. Evaluate option (d): This option suggests the system moves water through the body during filter feeding. While water is involved in the system's function, its primary role is not to move water through the body for filter feeding but for locomotion and manipulation of the environment.