Which of the following statement is true ?

Options

A. Vessels are multicellular with wide lumen
B. Tracheids are multicellular with narrow lumen
C. Vessels are uncellular with wide lumen
D. Tracheids are unicellular with wide lumen

Explanation

**Step-by-Step Text Solution:**

1. **Understanding Tracheids and Vessels:**
- Tracheids and vessels are both components of the xylem in vascular plants, responsible for the conduction of water and minerals.
- Tracheids are elongated, narrow cells that are dead at maturity and have thick, lignified walls.
- Vessels are also tubular structures but are wider and consist of a series of cells that are connected end to end.

2. **Characteristics of Tracheids:**
- Tracheids are unicellular in nature, meaning they originate from a single cell.
- They have a narrow lumen (the internal space of the cell) and are polygonal in cross-section.
- They are connected laterally to each other.

3. **Characteristics of Vessels:**
- Vessels are multicellular structures, formed from a series of cells that are aligned in a row.
- They have a wide lumen, which allows for more efficient water transport.
- The cells in vessels are connected through perforation plates that facilitate water movement.

4. **Evaluating the Statements:**
- The first statement claims that vessels are multicellular with a wide lumen, and tracheids are multicellular with a narrow lumen. This is incorrect because tracheids are unicellular.
- The second statement claims that vessels are unicellular with a wide lumen and tracheids are unicellular with a wide lumen. This is also incorrect because vessels are multicellular.

5. **Conclusion:**
- The only true statement is that vessels are multicellular with a wide lumen, and tracheids are unicellular with a narrow lumen.

**Final Answer:**
- The true statement is: "Vessels are multicellular with a wide lumen, and tracheids are unicellular with a narrow lumen."

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