Which of the following is true ?

Options

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

Answer

To determine which of the following statements is true regarding vessels and tracheids in plants, we can analyze each option based on the characteristics of these structures.

### Step-by-Step Solution:

1. **Understanding Vessels**:
- Vessels are long, cylindrical tube-like structures found in the xylem of flowering plants.
- They are composed of multiple cells, making them **multicellular**.
- The lumen (the internal space) of vessels is **wide**.

**Conclusion**: The statement that vessels are unicellular and have a narrow lumen is **false**.

2. **Analyzing the Second Option**:
- Since vessels are indeed **multicellular** and have a **wide lumen**, this statement is **true**.

3. **Understanding Tracheids**:
- Tracheids are also tube-like structures found in the xylem but differ from vessels.
- They are **unicellular**, meaning each tracheid is made up of a single cell.
- The lumen of tracheids is **narrow** and tapers at both ends.

**Conclusion**: The statement that tracheids are unicellular and have a wide lumen is **false**; they have a narrow lumen.

4. **Final Evaluation**:
- Based on the analysis:
- Option 1 is false (vessels are not unicellular and do not have a narrow lumen).
- Option 2 is true (vessels are multicellular and have a wide lumen).
- Option 3 is false (tracheids are unicellular but have a narrow lumen, not wide).
- Therefore, the only true statement is that vessels are multicellular and have a wide lumen.

### Final Answer:
The correct statement is: **Vessels are multicellular and have a wide lumen.**

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