The most primitive vascular plants are

Options

A. Cycas
B. ferns
C. moss
D. brown algae

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the most primitive vascular plants. To answer this, we need to identify which group of plants first developed vascular tissues.

2. **Plant Classification**: Plants are classified into different groups based on their characteristics. The main groups include:
- Algae (Thallophytes)
- Bryophytes
- Pteridophytes
- Gymnosperms
- Angiosperms

3. **Identifying Vascular Plants**: Vascular plants are those that have specialized tissues (xylem and phloem) for the conduction of water and nutrients.
- Algae and Bryophytes do not have vascular tissues, making them non-vascular plants.
- Pteridophytes are the first group of vascular plants, meaning they have developed vascular tissues.

4. **Determining the Most Primitive Vascular Plants**: Among the groups listed, pteridophytes are the first vascular plants. Within pteridophytes, ferns are a common example.

5. **Conclusion**: Therefore, the most primitive vascular plants are pteridophytes, specifically ferns.

**Final Answer**: The most primitive vascular plants are ferns (which belong to the group of pteridophytes).

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