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. ay or may not get crushed
D. it gets surrounded by primary phloem

Explanation

To answer the question regarding the fate of primary xylem in a dicot root showing extensive secondary growth, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Primary and Secondary Growth**:
- Primary growth occurs at the tips of roots and stems, leading to an increase in length.
- Secondary growth occurs due to the activity of lateral meristems (cambium), resulting in an increase in thickness.

2. **Role of Cambium**:
- The cambium is a lateral meristem that produces new cells.
- Cells produced towards the inner side of the cambium differentiate into secondary xylem.
- Cells produced towards the outer side differentiate into secondary phloem.

3. **Position of Primary Xylem**:
- In a dicot root, the primary xylem is located at the center of the root.
- During secondary growth, the cambium adds layers of secondary xylem and secondary phloem.

4. **Fate of Primary Xylem**:
- As secondary xylem is produced, the primary xylem remains in its original position at the center of the root.
- It does not get crushed or displaced; instead, it is retained in the center.

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

### Final Answer:
The primary xylem is retained in the center of the axis.

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