A common structural feature of vessel elements and sieve tube elements is

Options

A. having P protein
B. thick walls
C. pores on lateral wall
D. enucleate condition

Answer

To determine the common structural feature of vessel elements and sieve tube elements, let's analyze each option step by step:

1. **Understanding Vessel Elements and Sieve Tube Elements**:
- Vessel elements are specialized cells in the xylem responsible for water conduction.
- Sieve tube elements are part of the phloem and are involved in the transport of nutrients.

2. **Evaluating Option A: P Protein**:
- P protein is found in the cytoplasm of sieve tube elements but is not present in vessel elements.
- Therefore, this option is incorrect.

3. **Evaluating Option B: Thick Walls**:
- Thick walls are characteristic of vessel elements, which have lignified walls to provide structural support.
- Sieve tube elements, on the other hand, have thinner walls.
- Thus, this option is also incorrect.

4. **Evaluating Option C: Pores on Lateral Wall**:
- Pores are indeed present in vessel elements, allowing for water movement.
- However, sieve tube elements do not have the same type of pores; they have sieve plates at their ends for nutrient transport.
- Therefore, this option is incorrect as well.

5. **Evaluating Option D: Enucleate Condition**:
- The enucleate condition refers to cells that lack a nucleus.
- Both vessel elements and sieve tube elements are enucleate at maturity, which is a common feature.
- Thus, this option is correct.

6. **Conclusion**:
- The common structural feature of vessel elements and sieve tube elements is the enucleate condition (Option D).

### Final Answer:
The correct answer is **Option D: Enucleate condition**.