During the secondary growth in the dicotyledonous stems the cork cambium gives rise to :

Options

A. secondary xylem and secondary phloem
B. secondary cortex and cork
C. pith and medullary rays
D. multicellular hairs

Explanation

**Step-by-Step Solution:**

1. **Understanding Secondary Growth**: In dicotyledonous plants, secondary growth refers to the increase in thickness or girth of the plant stem and roots. This growth occurs due to the activity of two types of cambium: the vascular cambium and the cork cambium.

2. **Role of Cork Cambium**: The cork cambium is a type of lateral meristem that arises from the de-differentiation of the cortical tissue. It plays a crucial role in the formation of protective tissues.

3. **Products of Cork Cambium**: The cork cambium produces two main types of tissues:
- **Cork (Phellem)**: This is the outer protective layer that helps in preventing water loss and protects against physical damage.
- **Secondary Cortex (Phelloderm)**: This is formed on the inner side of the cork cambium and consists of living parenchyma cells.

4. **Evaluating the Options**:
- **Secondary Xylem and Secondary Phloem**: These are produced by the vascular cambium, not the cork cambium. Thus, this option is incorrect.
- **Secondary Cortex and Cork**: This is the correct answer, as cork cambium indeed produces both secondary cortex (phelloderm) and cork (phellem).
- **Pith and Medullary Rays**: These structures are also formed by the vascular cambium, making this option incorrect.
- **Multicellular Hairs**: These structures are associated with the epidermis and not produced by the cork cambium, so this option is also incorrect.

5. **Conclusion**: The correct answer to the question is that during secondary growth in dicotyledonous stems, the cork cambium gives rise to secondary cortex and cork.

**Final Answer**: Secondary cortex and cork.

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