Assertion: Heart wood is not involved in conduction function.
Reason: Tyloses and depositions of tannins, resins, and gums is common in duramen cells.

Options

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

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that heartwood is not involved in conduction function. Heartwood, or duramen, is the central part of a tree trunk, which is typically darker and denser than the surrounding wood.

2. **Understanding the Reason**: The reason provided states that tyloses and depositions of tannins, resins, and gums are common in duramen cells. Tyloses are outgrowths that can block the vessels in the xylem, and the deposition of tannins and other substances can further contribute to the non-conductive nature of heartwood.

3. **Analyzing the Assertion**: Heartwood is indeed non-functional in terms of water conduction. As trees mature, the inner xylem (heartwood) becomes filled with these substances (tannins, resins, gums), which makes it less effective or completely ineffective in conducting water.

4. **Analyzing the Reason**: The presence of tyloses and the accumulation of tannins, resins, and gums in heartwood cells is a significant factor that contributes to its non-conductive nature. These substances fill the vessel elements, preventing the flow of water.

5. **Conclusion**: Both the assertion and the reason are correct. The assertion accurately describes the non-conductive nature of heartwood, and the reason provides a valid explanation for this phenomenon.

6. **Final Statement**: Therefore, the correct answer is that both the assertion and the reason are true, and the reason correctly explains the assertion.