Echinoderms can be best described as which of the following?

• A. Marine, bilaterally symmetrical chordates with a notochord
• B. Terrestrial, bilaterally symmetrical protostomes with a closed circulatory system
• C. Marine, radially symmetrical deuterostomes with a water vascular system
• D. Freshwater, asymmetrical acoelomates with a gastrovascular cavity

Answer: (C)

Verified step by step guidance

1. Step 1: Begin by identifying the key characteristics of echinoderms. Echinoderms are marine animals, meaning they are primarily found in ocean environments.
2. Step 2: Understand their symmetry. Echinoderms exhibit radial symmetry, especially as adults, which means their body parts are arranged around a central axis.
3. Step 3: Recognize their developmental classification. Echinoderms are deuterostomes, which refers to their embryonic development where the anus forms before the mouth.
4. Step 4: Learn about their unique physiological system. Echinoderms possess a water vascular system, which is a network of hydraulic canals used for movement, feeding, and respiration.
5. Step 5: Compare the options provided in the problem. The correct description aligns with the characteristics of echinoderms: Marine, radially symmetrical deuterostomes with a water vascular system.