Which part is derived from both vascular cambial ring and cork cambium during secondary growth in dicot stem?

Options

A. Periderm
B. Bark
C. Cork
D. Bast

Answer

To answer the question "Which part is derived from both vascular cambial ring and cork cambium during secondary growth in dicot stem?", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Secondary Growth**: Secondary growth in dicot stems occurs due to the activity of two types of cambium: the vascular cambium and the cork cambium. The vascular cambium is responsible for producing secondary xylem (wood) and secondary phloem (inner bark), while the cork cambium produces cork (outer bark).

2. **Identifying the Cambium Functions**:
- **Vascular Cambium**: This layer produces new vascular tissues, specifically secondary xylem (wood) towards the inside and secondary phloem (inner bark) towards the outside.
- **Cork Cambium**: This layer produces cork, which is a protective outer layer of the stem.

3. **Analyzing the Options**:
- **Periderm**: This is the outer protective layer of the stem, which includes cork, cork cambium, and phelloderm. It is not directly derived from both cambial rings.
- **Bark**: Bark includes all tissues outside the vascular cambium, which consists of both living (secondary phloem) and dead (cork) tissues. It is derived from both the vascular cambium (producing phloem) and the cork cambium (producing cork).
- **Cork**: This is specifically the outermost layer produced by the cork cambium and does not involve the vascular cambium.
- **Bast**: This term typically refers to the inner phloem, which is produced by the vascular cambium and does not involve the cork cambium.

4. **Conclusion**: The part that is derived from both the vascular cambial ring and cork cambium during secondary growth in a dicot stem is **bark**. Bark encompasses both the secondary phloem (from vascular cambium) and cork (from cork cambium).

### Final Answer:
**Bark**