Cnidoblasts in a coelenterate help in

Options

A. anchorage
B. defense
C. prey capture
D. all of these

Answer

### Step-by-Step Solution:

1. **Understanding Cnidoblasts**:
- Cnidoblasts, also known as nematoblasts, are specialized cells found in coelenterates (like jellyfish, corals, and sea anemones).

2. **Location of Cnidoblasts**:
- These cells are primarily located on the tentacles of coelenterates.

3. **Structure of Cnidoblasts**:
- Cnidoblasts consist of a capsule, a shaft, and a thread-like tube. This structure allows them to perform their functions effectively.

4. **Functions of Cnidoblasts**:
- **Anchorage**: Cnidoblasts help coelenterates to anchor themselves to a substrate, providing stability in their environment.
- **Defense**: They serve as a defense mechanism against predators by delivering a sting, which can deter or incapacitate potential threats.
- **Offense (Prey Capture)**: Cnidoblasts are crucial for capturing prey. When triggered, they can release a stinging thread that can immobilize or kill small prey.

5. **Conclusion**:
- Given that cnidoblasts assist in anchorage, defense, and prey capture, the correct answer to the question is that they help in all of these functions.

### Final Answer:
- The answer is **Option D: All of these**.