Nematoblasts responsible for locomotion are

Options

A. Penetrants
B. Volvents
C. Glutinants
D. None of the above.

Answer

To solve the question regarding which type of nematoblasts are responsible for locomotion, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Nematoblasts**:
- Nematoblasts, also known as nematocysts, are specialized cells found in cnidarians (like jellyfish and corals) that contain a stinging structure used for defense and capturing prey.

2. **Identify the Types of Nematoblasts**:
- There are different types of nematoblasts, each serving a specific function. The options given are:
- Penetrant
- Volvent
- Glutinant
- None of the above

3. **Analyze Each Option**:
- **Penetrant**: This type is the largest nematocyst and is designed to pierce the body of prey and inject toxins. Its primary function is to paralyze prey, not locomotion.
- **Volvent**: This type has projections that help in holding and immobilizing prey. It is also not responsible for locomotion.
- **Glutinant**: This type is oval or elongated, lacks a butt and spine, and has a thread that is open at the tip. Glutinants are specifically known to assist in locomotion.
- **None of the above**: This option implies that none of the listed types are responsible for locomotion, which is incorrect since glutinants do serve this purpose.

4. **Conclusion**:
- After analyzing the options, we conclude that the nematoblasts responsible for locomotion are **glutinant nematoblasts** (Option 3).

### Final Answer:
The correct answer is **Glutinant** (Option 3).

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