Which part of Hydra is without supporting lamella?

Options

A. Basal disc
B. Central part of pedal disc
C. Tentacles
D. None of the above.

Answer

To answer the question "Which part of Hydra is without supporting lamella?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Hydra**:
- Hydra has a simple body structure that includes tentacles, a body column, a basal disc, and a gastrovascular cavity (coelenteron).
- The body wall of Hydra contains mesoglia, which acts as an internal skeleton.

2. **Identify the Parts of Hydra**:
- **Basal Disc**: This is the part that attaches Hydra to the substratum. It contains mesoglia.
- **Central Part of Pedal Disc**: The pedal disc is located at the base of Hydra. While the outer part has mesoglia, the central part is hollow.
- **Tentacles**: These are the extensions that contain mesoglia and are used for capturing prey.

3. **Analyze Each Option**:
- **Option A (Basal Disc)**: This part has supporting lamella (mesoglia) present.
- **Option B (Central part of Pedal Disc)**: This part is hollow and does not contain supporting lamella (mesoglia).
- **Option C (Tentacles)**: Tentacles have mesoglia present.
- **Option D (None of these)**: This option would imply all parts have supporting lamella, which is incorrect.

4. **Conclusion**:
- The part of Hydra that is without supporting lamella is the **Central Part of the Pedal Disc** (Option B).

### Final Answer:
The correct answer is **Option B: Central part of Pedal Disc**.

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