Zoochlorellae or Zooxanthellae of coloured Hydra occur in

Options

A. Epithelio-muscular cells
B. Nutritive cells
C. Mesogloea
D. Interstitial cells.

Answer

To answer the question regarding where Zoochlorellae or Zooxanthellae of colored Hydra occur, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Hydra**:
- Hydra has two main layers: the outer epidermis and the inner gastrodermis. The epidermis is derived from the ectoderm, while the gastrodermis is derived from the endoderm.

2. **Identify the Types of Cells in Hydra**:
- In the epidermis, we find epitheliomuscular cells, nidoblasts, germ cells, interstitial cells, nerve cells, and sensory cells.
- In the gastrodermis, we find nutritive muscular cells (also known as nutritive cells), gland cells, and similar interstitial, nerve, and sensory cells.

3. **Locate Zoochlorellae or Zooxanthellae**:
- Zoochlorellae (a type of green algae) and Zooxanthellae are symbiotic algae that live within the cells of the host organism. In the case of Hydra, these algae are specifically found in the nutritive muscular cells of the gastrodermis.

4. **Conclusion**:
- Based on the above information, the correct answer to the question is that Zoochlorellae or Zooxanthellae occur in the nutritive cells of Hydra.

### Final Answer:
The Zoochlorellae or Zooxanthellae of colored Hydra occur in the **nutritive muscular cells**.

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