Which gas is used in cryopreservation?

Options

A. Oxygen
B. Hydrogen
C. Sulphur
D. Nitrogen

Answer

**Step-by-Step Solution:**

1. **Understanding Cryopreservation:**
- Cryopreservation is a process used to preserve cells, tissues, or any biological constructs at very low temperatures. This is done to maintain their viability for future use.

2. **Identifying the Gases:**
- The question asks which gas is used in cryopreservation. The options provided are Oxygen, Hydrogen, Sulfur, and Nitrogen.

3. **Analyzing the Options:**
- Oxygen: Not typically used in cryopreservation as it can lead to oxidative stress in cells.
- Hydrogen: Not a common choice for cryopreservation.
- Sulfur: Not relevant in the context of cryopreservation.
- Nitrogen: Commonly used in cryopreservation due to its properties.

4. **Conclusion:**
- The gas used in cryopreservation is Nitrogen. It is chosen because it is effective for long-term storage of viable samples, maximizes energy efficiency, and is environmentally friendly.

5. **Final Answer:**
- The correct answer is **Nitrogen** (Option 4).

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