_______ is the process of regrowth of an organism from its lost body part.

Explanation

**Step-by-Step Text Solution:**

1. **Understanding the Concept**: The process we are looking for involves the ability of certain organisms to regrow lost body parts. This phenomenon is crucial in biology and is observed in various species.

2. **Identifying the Term**: The specific term that describes this process is "regeneration." Regeneration refers to the ability of an organism to regrow parts of its body that have been lost due to injury or other reasons.

3. **Examples of Regeneration**:
- **Hydra**: When a part of a Hydra is cut off, it can regenerate that lost part over time. This is a clear example of regeneration in action.
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