Which one of the following ( cell types ) contains the symbiotic Zoochlorellae in Hydra ?

Options

A. Epithelio muscular cells of epidermis
B. Endothelio muscular cells of gastrodermis
C. interstitial cells
D. Algae embedded in the mesoglea

Answer

To answer the question "Which one of the following (cell types) contains the symbiotic Zoochlorellae in Hydra?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Organism**: Recognize that Hydra is an organism belonging to the phylum Cnidaria. It has a symbiotic relationship with a type of algae known as Zoochlorella.

2. **Identify the Symbiotic Relationship**: Zoochlorella is a green algae that lives in symbiosis with Hydra. This relationship is beneficial for both organisms; the algae provide nutrients and oxygen to the Hydra, while the Hydra offers a suitable environment for the algae to thrive.

3. **Examine the Cell Types**: The options provided are:
- A. Epithelial muscular cells of the epidermis
- B. Endothelial muscular cells of the gastrodermis
- C. Interstitial cells
- D. Algae embedded in the mesothelial cells

4. **Determine the Correct Cell Type**: The correct cell type that contains the symbiotic Zoochlorella is the endothelial muscular cells of the gastrodermis. These cells are involved in the uptake of waste products from the Hydra, which the algae utilize for their growth, while simultaneously providing oxygen and nutrients to the Hydra.

5. **Final Answer**: Based on the analysis, the answer to the question is **B. Endothelial muscular cells of gastrodermis**.