secondary growth is best observed in

Options

A. (a) Teak and pine
B. (b) Deodar and fern
C. (c) Wheat and maidenhair fern
D. (d) sugarcane and sunflower

Answer

**Step-by-Step Solution:**

1. **Understanding Secondary Growth**: Secondary growth refers to the increase in thickness or girth of plants, which occurs due to the activity of the vascular cambium. This process leads to the formation of secondary xylem (wood) and secondary phloem.

2. **Role of Vascular Cambium**: The vascular cambium is a layer of meristematic tissue located between the primary xylem and phloem. It is responsible for producing new xylem and phloem cells, contributing to secondary growth.

3. **Types of Plants with Secondary Growth**: Secondary growth is primarily observed in dicotyledonous angiosperms (dicots) and gymnosperms. Monocotyledonous angiosperms (monocots) typically do not exhibit secondary growth.

4. **Analyzing the Options**:
- **Option A: Teak and Pine**: Teak is a dicot angiosperm, and pine is a gymnosperm. Both have vascular cambium and exhibit secondary growth. This option is a strong candidate.
- **Option B: Deodar and Fern**: Deodar is a gymnosperm, but fern is a pteridophyte, which does not have cambium and does not exhibit secondary growth. This option is incorrect.
- **Option C: Wheat and Maidenhair Fern**: Wheat is a monocot angiosperm, and maidenhair fern is a pteridophyte. Neither shows secondary growth. This option is incorrect.
- **Option D: Sugarcane and Sunflower**: Sugarcane is a monocot angiosperm, while sunflower is a dicot angiosperm. Since sugarcane does not exhibit secondary growth, this option is also incorrect.

5. **Conclusion**: The only option that includes plants capable of secondary growth is Option A: Teak and Pine. Therefore, secondary growth is best observed in these two types of plants.

**Final Answer**: Secondary growth is best observed in **Teak and Pine** (Option A).

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