Process of regeneration is seen in

Options

A. Fungi
B. Yeast
C. Algae
D. Planaria

Explanation

### Step-by-Step Solution:

1. **Understanding Regeneration**: Regeneration is a biological process where organisms can regrow lost or damaged parts. It is often associated with asexual reproduction, where a new individual can form from a part of the parent organism.

2. **Identifying the Organisms**: The question provides four options: fungus, yeast, algae, and planaria. We need to evaluate which of these organisms is known for its regenerative capabilities.

3. **Analyzing Each Option**:
- **Fungus**: While fungi can reproduce asexually through spores, they do not regenerate lost parts in the same way that some animals do.
- **Yeast**: Yeast is a unicellular organism that reproduces asexually by budding. It does not exhibit regeneration.
- **Algae**: Algae can reproduce asexually and can fragment, but they do not have the same regenerative capabilities as some multicellular organisms.
- **Planaria**: Planaria are flatworms known for their remarkable ability to regenerate. If a planarian is cut into pieces, each piece can regenerate into a complete organism.

4. **Conclusion**: Based on the analysis, the organism that exhibits the process of regeneration is **planaria**.

### Final Answer:
**Planaria** is the organism where the process of regeneration is prominently observed.

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