Interstitial cells take part in

Options

A. Sealing the body layers
B. Transfer of materials between epidermis and gastrodermis
C. Replacement of old worn out cells
D. Formation of neurosensory complex.

Answer

**Step-by-Step Solution:**

1. **Understand the Structure of Hydra**: Hydra has a body wall made up of two main layers: the outer epidermis (derived from ectoderm) and the inner gastrodermis. Between these two layers is the mesoglea, which is acellular and indicates that Hydra is diploblastic (having two germ layers).

2. **Identify the Role of Interstitial Cells**: Interstitial cells are found in both the epidermis and gastrodermis of Hydra. They are among various cell types present in these layers, including nerve cells, sensory cells, epithelial muscular cells, and germ cells.

3. **Function of Interstitial Cells**: These cells act as reserve cells, meaning they have the ability to regenerate and can differentiate into various cell types. This property is known as totipotency, allowing them to replace old or worn-out cells.

4. **Eliminate Incorrect Options**: The question asks what role interstitial cells play. They do not function in sealing body parts or transferring materials, nor do they form the neurosensory complex. Their primary role is in cell replacement and regeneration.

5. **Select the Correct Answer**: Based on the information gathered, the correct answer is that interstitial cells take part in the replacement of old worn-out cells.

**Final Answer**: Interstitial cells take part in the replacement of old worn-out cells.

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