Secondary growth is usually absent in

Options

A. Dicot root and Dicot stem
B. Monocot root and Monocot stem
C. Dicot root and Monocot stem
D. Monocot root and Dicot stem

Answer

**Step-by-Step Solution:**

1. **Understanding Secondary Growth**: Secondary growth refers to the increase in thickness or girth of a plant's root or stem. This growth is primarily due to the activity of the cambium, a type of lateral meristem.

2. **Role of Cambium**: The cambium is a layer of tissue that produces new cells, contributing to the thickening of the plant. It is responsible for the formation of secondary vascular tissues (xylem and phloem).

3. **Identifying Plant Types**:
- **Dicots**: In dicot plants, both the root and stem typically have cambium present, allowing for secondary growth.
- **Monocots**: In monocot plants, the cambium is usually absent in both the root and stem, which means they do not undergo secondary growth.

4. **Conclusion**: Since secondary growth is dependent on the presence of cambium, and monocots lack this tissue, secondary growth is usually absent in monocot roots and stems.

5. **Final Answer**: Therefore, the correct answer to the question "Secondary growth is usually absent in" is **monocot roots and monocot stems**.

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