All of the following are related to Aplysia, except.

Options

A. Triploblastic
B. Eucoelomate
C. Bilaterally symmetrical
D. Water vascular system

Answer

To solve the question "All of the following are related to Aplysia, except," we need to analyze each of the given options and determine which one does not relate to Aplysia.

### Step-by-Step Solution:

1. **Identify Aplysia Characteristics**: Aplysia, commonly known as sea hares, are marine gastropod mollusks. They have specific characteristics that we need to evaluate against the options provided.

2. **Evaluate Option 1: Triploblastic**
- Aplysia is indeed triploblastic, meaning it has three primary germ layers: ectoderm, mesoderm, and endoderm.
- **Conclusion**: This option is related to Aplysia.

3. **Evaluate Option 2: Coelomate**
- Aplysia is classified as a coelomate organism, which means it has a true coelom (body cavity) that is lined by mesodermal tissue.
- **Conclusion**: This option is also related to Aplysia.

4. **Evaluate Option 3: Bilaterally Symmetrical**
- Aplysia exhibits bilateral symmetry, meaning it can be divided into two mirror-image halves along one plane.
- **Conclusion**: This option is related to Aplysia.

5. **Evaluate Option 4: Water Vascular System**
- Aplysia does not possess a water vascular system. This system is characteristic of echinoderms (like starfish and sea urchins), not mollusks.
- **Conclusion**: This option is NOT related to Aplysia.

### Final Answer:
The correct answer is the option that states "Water vascular system," as it is the only characteristic that does not relate to Aplysia.

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