Growth in the first 10-13 years of age is controlled by

Options

A. Somatotrophic hormone
B. Thyroxine
C. Thymosin
D. Gonadotrophic hormone

Answer

**Step-by-Step Solution:**

1. **Understanding the Age Range**: The question refers to growth during the first 10-13 years of age, a period often associated with early childhood and pre-puberty.

2. **Identifying Key Hormones**: The options provided are somatotropic hormone (growth hormone), thyroxin, thymosin, and gonadotropic hormone. We need to determine which hormone is primarily responsible for growth during this age.

3. **Role of Somatotropic Hormone**: The somatotropic hormone, also known as growth hormone (GH), is crucial for overall growth and development throughout childhood. However, it is regulated by other factors.

4. **Thymosin's Function**: Thymosin is produced by the thymus gland and is particularly important during puberty. It plays a role in regulating the immune system and also influences the release of growth hormone from the pituitary gland.

5. **Evaluating Other Hormones**:
- **Thyroxin**: This hormone, produced by the thyroid gland, is involved in regulating metabolism but does not directly control growth.
- **Gonadotropic Hormones**: These hormones target the gonads and are more involved in sexual development rather than general growth.

6. **Conclusion**: While growth hormone is essential for growth, thymosin plays a critical role in regulating its release during the early years of life, particularly as the body approaches puberty. Therefore, the correct answer is thymosin.

**Final Answer**: The growth in the first 10-13 years of age is controlled by **thymosin**.

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