Which of the following mammals has scrotal testes?

Options

A. Prototherians
B. All placental mammals
C. Elephant
D. Man

Answer

To determine which of the following mammals has scrotal testes, we need to understand the concept of scrotal testes and the significance of their location.

### Step-by-Step Solution:

1. **Definition of Scrotal Testes**:
- Scrotal testes refer to the male reproductive organs (testes) that are located in the scrotum, which is an external pouch of skin. This positioning is crucial for regulating temperature.

2. **Importance of Temperature**:
- Spermatogenesis, the process of sperm production, requires a temperature lower than the normal body temperature. For optimal sperm production, the testes need to be at a temperature approximately 3.1 degrees Celsius lower than the body temperature.

3. **Human Example**:
- In humans, the body temperature is around 96-97 degrees Fahrenheit (approximately 36-37 degrees Celsius). The scrotum allows the testes to remain cooler than the body temperature, facilitating effective spermatogenesis.

4. **Comparison with Other Mammals**:
- In contrast, some mammals such as prototherians (like the platypus and echidna) have their testes located inside their bodies. Their internal body temperature is suitable for spermatogenesis, so they do not require scrotal testes.
- Additionally, many placental mammals, including elephants, also have their testes located internally.

5. **Conclusion**:
- Based on the information above, the only mammal among the options that has scrotal testes is humans. Therefore, the answer to the question is that scrotal testes are found in humans.

### Final Answer:
The mammal that has scrotal testes is **humans**.

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