Which one of the following is not a part of phloem :

Options

A. Sieve tube
B. Companion cells
C. Phloem parenchyma
D. Vessel

Answer

To solve the question "Which one of the following is not a part of phloem?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Components of Phloem**:
- Phloem is a type of vascular tissue in plants responsible for the transport of nutrients, particularly sugars (sucrose).
- The main components of phloem include:
- Sieve tube elements
- Companion cells
- Phloem parenchyma
- Phloem fibers

2. **Identify the Options Given**:
- The options provided are:
- Sieve tube
- Companion cells
- Phloem parenchyma
- Vessel

3. **Analyze Each Option**:
- **Sieve tube**: This is a component of phloem.
- **Companion cells**: These are also part of phloem and support sieve tubes.
- **Phloem parenchyma**: This is another component of phloem, involved in storage and transport.
- **Vessel**: This refers to xylem vessels, which are part of xylem, not phloem.

4. **Conclusion**:
- Since vessel is the only option that does not belong to phloem, the correct answer is **Vessel**.

### Final Answer:
The correct option is **Vessel**, as it is not a part of phloem.

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