Coronavirus is highly dangerous and life-threatening for elderly. This is due to a progressive decrease in secretion of

Options

A. Adrenaline
B. Vasopressin
C. Thymosin
D. FSH

Answer

To solve the question regarding why coronavirus is highly dangerous and life-threatening for the elderly, we need to identify the hormone whose secretion progressively decreases with age and is related to immunity.

### Step-by-Step Solution:

1. **Understanding the Context**:
- The question states that coronavirus poses a higher risk to the elderly. This is often linked to the immune system's effectiveness, which tends to decline with age.

2. **Analyzing the Options**:
- **Adrenaline**: This hormone is related to the body's stress response. Its secretion does not significantly decrease with age, so it is not the correct answer.
- **Vasopressin**: This hormone helps regulate water balance and salt levels in the body. Its secretion is not primarily linked to immune function and does not decrease significantly with age. Thus, it is not the correct answer.
- **Thymosin**: This hormone is crucial for the development and function of T-cells, which are essential components of the immune system. Research indicates that thymosin levels decrease with age, leading to a weakened immune response.
- **FSH (Follicle Stimulating Hormone)**: This hormone is involved in reproductive processes and does decrease with age, particularly in women. However, it is not directly related to the immune system's function.

3. **Identifying the Correct Answer**:
- Given the analysis, **thymosin** is the hormone that decreases with age and is directly related to immunity. Therefore, the correct answer is thymosin.

4. **Conclusion**:
- The progressive decrease in the secretion of thymosin contributes to the increased vulnerability of elderly individuals to infections, including coronavirus.

### Final Answer:
The correct answer is **thymosin**.