Which pair of cells is present in epidermis of Hydra but not in its gastrodermis

Options

A. Stinging cells and interstitial cells
B. Gland cells and germ cells
C. Stinging cells and germ cells
D. Stinging cells and gland cells.

Answer

To answer the question "Which pair of cells is present in the epidermis of Hydra but not in its gastrodermis?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Hydra**:
- Hydra has two main layers: the epidermis (outer layer) and the gastrodermis (inner layer).

2. **Identify Cells in the Epidermis**:
- The epidermis of Hydra contains several types of cells:
- Epithelio-muscular cells
- Nidocytes (stinging cells)
- Germ cells
- Interstitial cells
- Sensory cells
- Nerve cells

3. **Identify Cells in the Gastrodermis**:
- The gastrodermis contains:
- Nutritive muscular cells
- Gland cells
- Interstitial cells
- Sensory cells
- Nerve cells

4. **Compare the Cell Types**:
- From the comparison, we can see that:
- Interstitial cells, sensory cells, and nerve cells are present in both the epidermis and gastrodermis.
- Gland cells are exclusive to the gastrodermis.
- Epithelio-muscular cells and nidocytes (stinging cells) are found only in the epidermis.

5. **Determine the Unique Pair of Cells**:
- The unique pair of cells that is present in the epidermis but not in the gastrodermis is:
- Nidocytes (stinging cells)
- Germ cells

6. **Conclusion**:
- Therefore, the correct answer to the question is that the pair of cells present in the epidermis of Hydra but not in its gastrodermis is **Nidocytes and Germ cells**.

### Final Answer:
The pair of cells present in the epidermis of Hydra but not in its gastrodermis is **Nidocytes (stinging cells) and Germ cells**.

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