A piece of Hydra will regenerate into a full Hydra if it contains a part of

Options

A. Epidermis
B. Epidermis, gastrodermis, and interstitial cells
C. Basal disc
D. Epidermis, gastrodermis, and tentacles

Answer

To determine what part of a Hydra is necessary for regeneration into a full organism, we need to analyze the structure and regenerative capabilities of Hydra.

### Step-by-Step Solution:

1. **Understanding Hydra's Structure**: Hydra is a simple organism belonging to the phylum Cnidaria. It has two main body layers: the epidermis and the gastrodermis.

2. **Regenerative Ability**: Hydra is known for its remarkable ability to regenerate. This ability is due to the presence of specific cells that can differentiate into various cell types needed for regeneration.

3. **Key Components for Regeneration**: For a piece of Hydra to regenerate into a full organism, it must contain:
- **Epidermis**: The outer layer of cells.
- **Gastrodermis**: The inner layer that lines the digestive cavity.
- **Interstitial Cells**: These are undifferentiated cells that can develop into various cell types, including those needed for the epidermis and gastrodermis.

4. **Conclusion**: Therefore, a piece of Hydra will regenerate into a full Hydra if it contains parts of the epidermis, gastrodermis, and interstitial cells.

5. **Correct Answer**: The correct answer is that a piece of Hydra will regenerate into a full Hydra if it contains parts of the epidermis, gastrodermis, and interstitial cells.