Vascular bundles of roots are

Options

A. Conjoint
B. Concentric
C. Bicollateral
D. Radial

Answer

To solve the question regarding the type of vascular bundles found in roots, we will analyze the options provided and determine the correct answer step by step.

### Step 1: Understand the Types of Vascular Bundles
Vascular bundles are arrangements of xylem and phloem in plants. The main types of vascular bundles are:
- **Conjoined**: Xylem and phloem are found together in a single bundle.
- **Concentric**: Xylem and phloem are arranged in a concentric manner, one surrounding the other.
- **Bicollateral**: Xylem and phloem are present on both sides of the xylem in a single bundle.
- **Radial**: Xylem and phloem are arranged in separate groups, alternating in a radial pattern.

### Step 2: Analyze the Options
1. **Conjoined**: This type is typically found in leaves and stems, not in roots.
2. **Concentric**: This arrangement is found in some monocots and pteridophytes but is absent in roots.
3. **Bicollateral**: This type is found in certain stems, particularly in the Solanaceae family, but not in roots.
4. **Radial**: In roots, xylem and phloem are arranged in separate groups at alternate radial positions.

### Step 3: Identify the Correct Answer
From the analysis, the only option that accurately describes the arrangement of vascular bundles in roots is **radial**. This is because in roots, xylem and phloem are indeed found in separate groups, which is characteristic of radial vascular bundles.

### Conclusion
The correct answer to the question "Vascular bundles of roots are" is **radial**.

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