Assertin :- A true breeding line shows the the stable trait inheritance and expression for several generatins.
Reason :- A true breeding line is one that have undergoes continuous cross pollination.

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
B. If both Assertion & Reason are trur but Reason is not a correct explanation of the Assertion.
C. If Assertion is True but the Reason is Flase.
D. If both Assertion & Reason are false.

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that a true breeding line shows stable trait inheritance and expression for several generations.
- This means that when a plant or organism is true breeding, it consistently passes on the same traits to its offspring over multiple generations.

2. **Defining True Breeding Line**:
- A true breeding line refers to a group of organisms that, when self-pollinated or bred together, produce offspring that are identical to themselves in terms of specific traits.
- For example, if a plant is true breeding for flower color (e.g., purple), all offspring produced from self-pollination will also have purple flowers.

3. **Mendel's Contribution**:
- Gregor Mendel, known as the father of genetics, studied true breeding lines in pea plants.
- He observed that traits remained stable and consistent across generations when plants were self-pollinated.

4. **Evaluating the Reason**:
- The reason states that a true breeding line undergoes continuous cross-pollination.
- This is incorrect because true breeding lines are established through self-pollination, not cross-pollination. Cross-pollination introduces genetic variation, which is not characteristic of true breeding lines.

5. **Conclusion**:
- Since the assertion is true (true breeding lines show stable trait inheritance), but the reason is false (true breeding lines do not undergo continuous cross-pollination), the correct answer is that only the assertion is true.

### Final Answer:
- The assertion is true, and the reason is false. Therefore, the correct option is that only the assertion is true.

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