Assertion: Human beings are not suitable for breeding experiments to investigate the human traits.
Reason: Their lifespan is small.

Options

A. If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
B. If both Assertion and Reason are true and the Reason is not the correct explanation of the Assertion.
C. If Assertion is true but the Reason is false.
D. If both Assertion and Reason are false.

Answer

To solve the question regarding the assertion and reason provided, we need to analyze both statements carefully.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Human beings are not suitable for breeding experiments to investigate human traits."
- This is true because human beings have certain characteristics that make them less ideal for breeding experiments compared to other organisms, such as fruit flies or pea plants.

2. **Understanding the Reason**:
- The reason given is "Their lifespan is small."
- This statement is misleading. In fact, human beings have a relatively long lifespan compared to many other organisms used in breeding experiments. Therefore, this reason is not accurate.

3. **Evaluating the Relationship**:
- The assertion is true, but the reason provided is false.
- A suitable reason for why humans are not used in breeding experiments would include ethical concerns, long generation times, and the complexity of human traits, rather than lifespan.

4. **Conclusion**:
- Since the assertion is true and the reason is false, the correct answer to the question is that the assertion is true, but the reason is not a correct explanation of the assertion.

### Final Answer:
- The assertion is true, and the reason is false.