Assertion: The short-legged sheep is a pure breed.
Reason: They appeared by mutation in one generation.

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

**Step-by-Step Solution:**

1. **Understanding the Assertion**: The assertion states that "the short-legged sheep is a pure breed." This implies that the short-legged sheep consistently produces offspring with the same short-legged trait when bred among themselves.

2. **Understanding the Reason**: The reason provided is that "they appeared by mutation in one generation." This suggests that the short-legged trait arose suddenly due to a mutation, rather than being a trait that has been passed down through generations.

3. **Historical Context**: In 1971, the Ancon sheep, which had short legs, was first observed. This breed is known to have a homozygous recessive genotype that results in the short-legged phenotype. This indicates that the trait is genetically stable and can be considered a pure breed.

4. **Evaluating the Assertion and Reason**:
- The assertion is true because the Ancon sheep can be classified as a pure breed due to the stable expression of the short-legged trait.
- The reason is false because the appearance of the short-legged sheep was not merely a single mutation in one generation; it is a result of a stable genetic trait that has been inherited.

5. **Conclusion**: Therefore, the correct evaluation is that the assertion is true, but the reason is false.

**Final Answer**: Assertion is true, but the reason is false.

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