In which of the vascular bundles phloem is surrounded by xylem

Options

A. Collateral
B. Amphivasal
C. Amphicribral
D. Radial

Answer

To answer the question "In which of the vascular bundles is phloem surrounded by xylem?", we need to analyze the different types of vascular bundles mentioned in the options provided.

### Step-by-Step Solution:

1. **Understand Vascular Bundles**: Vascular bundles are arrangements of xylem and phloem in plants that facilitate the transport of water, nutrients, and food. There are different types of vascular bundles based on the arrangement of xylem and phloem.

2. **Identify the Types of Vascular Bundles**:
- **Collateral**: In collateral vascular bundles, the phloem is located outside the xylem. They are arranged side by side on the same radius.
- **Amphibazole**: In amphibazole vascular bundles, the phloem is surrounded by xylem on all sides, forming a concentric arrangement.
- **Amphicribral**: In amphicribral bundles, there is a central strand of xylem surrounded by a ring of phloem, but they are not on the same radius.
- **Radial**: In radial vascular bundles, the xylem and phloem are separated by non-vascular tissues.

3. **Analyze Each Option**:
- **Collateral**: Incorrect, as phloem is outside xylem.
- **Amphibazole**: Correct, as phloem is surrounded by xylem on all sides.
- **Amphicribral**: Incorrect, as phloem surrounds xylem but not on the same radius.
- **Radial**: Incorrect, as xylem and phloem are separated by non-conductive tissues.

4. **Conclusion**: The correct answer is **Amphibazole**, where phloem is completely surrounded by xylem.

### Final Answer:
The vascular bundle in which phloem is surrounded by xylem is called **Amphibazole**.