What is the fate of primary xylem in a dicot root showing extensive secondary growth?

Options

A. It is retained in the centre of the axis
B. It gets crushed
C. May or may not get crushed
D. It gets surrounded by primary phloem

Explanation

### Step-by-Step Solution:

1. **Understanding Primary Xylem**: The primary xylem is the first formed xylem tissue in a plant, which is responsible for the conduction of water and minerals. In dicot roots, it is located centrally.

2. **Secondary Growth in Dicot Roots**: Secondary growth refers to the increase in thickness or girth of the plant, which occurs due to the activity of the vascular cambium. This growth results in the formation of secondary xylem (wood) and secondary phloem.

3. **Position of Primary Xylem During Secondary Growth**: As secondary growth occurs, the primary xylem remains in its original position at the center of the root. It does not get pushed outward like the primary phloem.

4. **Fate of Primary Xylem**: During extensive secondary growth, the primary xylem is retained in the center of the root and does not get crushed or displaced. It continues to exist at the core of the root structure.

5. **Conclusion**: Therefore, the fate of the primary xylem in a dicot root showing extensive secondary growth is that it is retained in the center of the axis.

### Final Answer:
The primary xylem in a dicot root showing extensive secondary growth is retained in the center of the axis.

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