The water vascular system of a sea star functions in __________.

• A. digestion
• B. pumping water for swimming movements
• C. reproduction
• D. keeping all parts of the body moist at low tide
• E. movement of the tube feet

Answer: (E)

Verified step by step guidance

1. Understand the water vascular system: The water vascular system is a network of hydraulic canals unique to echinoderms, such as sea stars, and is crucial for their locomotion.
2. Identify the components: The system includes structures like the madreporite, stone canal, ring canal, radial canals, and tube feet, which are essential for movement.
3. Focus on tube feet: The tube feet are small, flexible, and extendable appendages that are part of the water vascular system. They play a key role in movement, feeding, and respiration.
4. Mechanism of movement: Water enters through the madreporite, travels through the canals, and fills the tube feet. The hydraulic pressure allows the tube feet to extend and contract, enabling the sea star to move.
5. Conclusion: The primary function of the water vascular system in sea stars is to facilitate the movement of the tube feet, which allows the sea star to locomote, capture food, and interact with its environment.