A: Sieve tubes and companion cells are related ontogenetically.
R: Both develop from same mother cell.

Options

A. If both Assertion & Reason are true and the reason is the correct expalanation of the assertion. Then mark (1).
B. If Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
C. If Assertion is true statement but Reason is false, then mark (3).
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To solve the assertion and reason question regarding sieve tubes and companion cells, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Assertion**: The assertion states that "Sieve tubes and companion cells are related ontogenetically." This means we need to determine if sieve tubes and companion cells share a common developmental origin.

2. **Understand the Reason**: The reason provided is "Both develop from the same mother cell." This implies that if this statement is true, it would support the assertion.

3. **Examine the Relationship**: In the phloem of angiosperms, sieve tubes and companion cells are indeed specialized cells that work together in the transport of nutrients. They are derived from the same precursor cell during development.

4. **Confirm the Developmental Origin**: Both sieve tubes and companion cells originate from a common mother cell known as the cambial cell or a meristematic cell. This confirms that they are ontogenetically related.

5. **Evaluate the Truthfulness**: Since both the assertion and the reason are true, and the reason correctly explains the assertion, we can conclude that both statements are accurate.

6. **Final Conclusion**: Therefore, the correct answer is that both the assertion and reason are true, and the reason is the correct explanation of the assertion.

### Final Answer:
Both the assertion and reason are true, and the reason is the correct explanation of the assertion.

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