Which one is enucleacted ?

Options

A. Companion cell
B. Sieve cell
C. Tracheid
D. Vessel

Answer

To determine which of the given cells is enucleated, we need to understand the definition of enucleated cells and examine the options provided.

### Step-by-Step Solution:

1. **Understand the term "enucleated":**
- Enucleated refers to a cell that does not contain a nucleus. This can apply to both plant and animal cells.

2. **Review the options:**
- The options provided are:
- A) Companion cell
- B) Seed cell
- C) Trachea
- D) Vessel

3. **Identify the types of cells:**
- Companion cells and sieve cells are components of the phloem, which is responsible for transporting food (especially sugars) in plants.
- Tracheids and vessels are components of the xylem, which conducts water and minerals.

4. **Analyze each option:**
- **Companion Cell:** Contains a nucleus and assists in the function of sieve cells.
- **Seed Cell:** Typically contains a nucleus as it is part of the reproductive structure of the plant.
- **Trachea:** This term generally refers to a part of the respiratory system in animals, but if referring to plant tracheids, they do have a nucleus.
- **Vessel:** In the context of xylem vessels, these are also nucleated cells.

5. **Focus on Sieve Cells:**
- Sieve cells are specialized cells in the phloem that lack a nucleus. They rely on companion cells for metabolic support.

6. **Conclusion:**
- The enucleated cell among the options is the **sieve cell** (option B).

### Final Answer:
The enucleated cell is **sieve cell**.