In Hydra, all old cells are replaced in

Options

A. 15 days
B. 30 days
C. 45 days
D. 60 days

Answer

**Step-by-Step Solution:**

1. **Understanding Hydra's Regeneration Ability**: Hydra is known for its remarkable ability to regenerate. This means that it can replace old or damaged cells and even regenerate lost body parts.

2. **Cell Replacement Process**: In Hydra, the epithelial cells in the body column continuously proliferate. This means that new cells are formed to replace the old ones. The replacement occurs primarily at the poles of the polyp.

3. **Time Frame for Cell Replacement**: It is noted that the process of replacing all old cells in Hydra takes approximately 40 to 50 days. This is the time required for the complete turnover of cells in Hydra.

4. **Evaluating the Options**: The question provides several options: 15 days, 30 days, 45 days, and 60 days. Based on the information about Hydra's cell replacement time frame:
- 15 days: Incorrect
- 30 days: Incorrect
- 45 days: Correct (as it falls within the 40 to 50 days range)
- 60 days: Incorrect

5. **Conclusion**: The correct answer is 45 days, as it aligns with the regeneration and cell replacement time frame of Hydra.

**Final Answer**: 45 days

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