A: Human bone has haversian canals.
R: Haversion canals are interconnected by Volkmann's canals.

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Human bone has Haversian canals."
- Haversian canals are indeed present in human bones, specifically in the compact bone tissue. They are microscopic tubes that contain blood vessels and nerves, which are essential for the nourishment and communication of bone cells (osteocytes).

2. **Understanding the Reason (R)**:
- The reason states that "Haversian canals are interconnected by Volkmann's canals."
- This statement is also true. Volkmann's canals (or perforating canals) connect Haversian canals to each other and to the periosteum (the outer layer of bone). They allow for the passage of blood vessels and nerves between the Haversian systems.

3. **Evaluating the Truth of Both Statements**:
- Both the assertion and the reason are true. The Haversian system is a key structural feature of compact bone, and the interconnection by Volkmann's canals is an important aspect of bone physiology.

4. **Conclusion**:
- Since both the assertion and the reason are true, and the reason correctly explains the assertion, we can conclude that the relationship between the two statements is valid.

### Final Answer:
Both the assertion (A) and the reason (R) are true, and the reason correctly explains the assertion.

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