During secondary growth, a complete ring is formed by

Options

A. Only fascicular cambia
B. Only interfascicular cambia
C. Fascicular (vascular) cambia and interfascicular cambia
D. Fascicular cambia + Phellogen

Answer

To answer the question about what forms a complete ring during secondary growth, we will analyze the components involved in this process step by step.

### Step-by-Step Solution:

1. **Understanding Secondary Growth**: Secondary growth refers to the increase in girth of the plant, primarily seen in dicots and gymnosperms. It occurs due to the activity of the vascular cambium and cork cambium.

2. **Identifying Cambium Types**:
- **Fascicular Cambium**: This is the cambium located between the xylem and phloem within the vascular bundles (fascicles).
- **Interfascicular Cambium**: This is the cambium that forms between the vascular bundles in the regions where there are no vascular tissues.

3. **Formation of the Complete Ring**: During secondary growth, the fascicular cambium and the interfascicular cambium together form a continuous ring of cambium around the stem. This ring is essential for the production of secondary xylem (wood) and secondary phloem.

4. **Conclusion**: Therefore, the complete ring during secondary growth is formed by the combination of both the fascicular cambium and the interfascicular cambium.

### Final Answer:
The complete ring during secondary growth is formed by both fascicular cambium and interfascicular cambium.

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