Vascular bundel with `2:1` ratio of phloem and xylem is

Options

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

Answer

To solve the question regarding the type of vascular bundle with a 2:1 ratio of phloem to xylem, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Vascular Bundles**: Vascular bundles are structures in plants that contain xylem and phloem, responsible for the transport of water, nutrients, and food.

2. **Identify Types of Vascular Bundles**: There are several types of vascular bundles based on the arrangement of xylem and phloem:
- **Collateral**: Xylem is located on the inner side and a single strand of phloem is on the outer side.
- **Bicollateral**: Xylem is in the center with two strands of phloem on either side.
- **Amphivasal**: Xylem surrounds the phloem.
- **Amphicrebral**: Phloem surrounds the xylem.

3. **Analyze the Ratio**: The question specifies a 2:1 ratio of phloem to xylem. This means there are two strands of phloem for every one strand of xylem.

4. **Determine the Correct Type**:
- In **collateral** bundles, there is only 1 phloem to 1 xylem, which does not fit the 2:1 ratio.
- In **bicollateral** bundles, there are 2 phloem strands surrounding a single xylem strand, which fits the 2:1 ratio.
- In **amphivasal** and **amphicrebral** bundles, the arrangement does not support a 2:1 ratio as they involve surrounding structures.

5. **Conclusion**: The vascular bundle with a 2:1 ratio of phloem to xylem is the **bicollateral** type.

### Final Answer:
The vascular bundle with a 2:1 ratio of phloem to xylem is **bicollateral**.

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