At the onset of puberty _____is released by testes.

Options

A. thyroxin
B. insulin
C. testosterone
D. adrenaline

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which hormone is released by the testes at the onset of puberty.

2. **Identifying the Hormones**: We need to consider the hormones that are associated with the testes and their functions during puberty.

3. **Analyzing Options**:
- **Option 1: Rock scene** - This is incorrect as it refers to a hormone that regulates basal metabolic rate, not related to the testes.
- **Option 2: Insulin** - This is incorrect as insulin regulates blood sugar levels and is not released by the testes.
- **Option 3: Testosterone** - This is the correct answer. Testosterone is the hormone released by the testes at the onset of puberty and is responsible for the development of male reproductive tissues and the production of sperm.
- **Option 4: Adrenaline** - This is incorrect as adrenaline is released during stress and does not relate to the testes.

4. **Conclusion**: The hormone released by the testes at the onset of puberty is **Testosterone**.

**Final Answer**: At the onset of puberty, **Testosterone** is released by the testes.

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