Which of the following is not applicable for members of the phylum Echinodermata?

Options

A. Habitat - Exclusively marine
B. Symmetry - Adults are radially symmetrical
C. Body system- Presence of canal system due to the folding of the body wall
D. Development - Indirect

Answer

To solve the question "Which of the following is not applicable for members of the phylum Echinodermata?", we need to analyze the characteristics of Echinodermata and identify which statement does not apply to them.

### Step-by-Step Solution:

1. **Understanding Echinodermata**:
- Echinodermata are known as spiny-bodied animals. The term "Echinodermata" comes from "echino" meaning spiny and "derm" meaning skin.

2. **Habitat**:
- All members of Echinodermata are exclusively marine. This means they live in oceanic environments.

3. **Body Structure**:
- Echinoderms possess an endoskeleton made of calcareous ossicles. They do not have an exoskeleton like arthropods.

4. **Symmetry**:
- Adults are radially symmetrical, meaning they can be divided into similar halves by multiple planes. However, their larvae are bilaterally symmetrical.

5. **Organ System**:
- Echinoderms have an organ system level of organization. This includes a complete digestive system with a mouth located on the lower side and an anus on the upper side.

6. **Water Vascular System**:
- A key characteristic of Echinodermata is the water vascular system, which is involved in locomotion, feeding, and respiration. It is important to note that this is different from a "water canal system," which is associated with Porifera (sponges).

7. **Identifying the Incorrect Statement**:
- The question asks for a statement that is not applicable to Echinodermata.
- If one of the options mentions a "water canal system" instead of a "water vascular system," that would be the incorrect statement.

8. **Conclusion**:
- Based on the analysis, the statement regarding the "water canal system" is not applicable to Echinodermata. Therefore, the correct answer is the option that mentions this incorrect term.

### Final Answer:
The option that states "water canal system" is not applicable for members of the phylum Echinodermata.

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