Nematocysts of Hydra occur in maximum number over

Options

A. Gastrodermis
B. Basal disc
C. Gonads
D. Tentacles.

Answer

To answer the question "Nematocysts of Hydra occur in maximum number over," we need to analyze the options provided and understand the anatomy of Hydra, particularly where nematocysts are located.

### Step-by-Step Solution:

1. **Understand the Structure of Hydra**:
- Hydra is a member of the phylum Cnidaria. It has a simple body structure that includes a mouth, tentacles, and a basal disc.

2. **Identify Nematocysts**:
- Nematocysts are specialized stinging organelles found within cnidocytes (stinging cells) of Hydra. These organelles are responsible for capturing prey and defense.

3. **Evaluate the Options**:
- **Gastrodermis**: This is the inner layer of cells that lines the digestive cavity. While it plays a role in digestion, it does not contain a high concentration of nematocysts.
- **Basal Disc**: This is the structure that anchors the Hydra to a substrate. It does not have nematocysts as its primary function is attachment, not prey capture.
- **Gonads**: These are reproductive structures (testes and ovaries) and are not involved in capturing prey, hence they do not contain nematocysts.
- **Tentacles**: These are the elongated structures that extend from the body of Hydra. They are equipped with a high concentration of nematocysts, which are used to capture prey by stinging.

4. **Conclusion**:
- The maximum number of nematocysts in Hydra occurs in the **tentacles**. Therefore, the correct answer is **tentacles**.

### Final Answer:
The nematocysts of Hydra occur in maximum number over **tentacles**.

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