Some vascular bundles are described as open because these

Options

A. are surrounded by pericycle but no endodermis
B. are capable of producing secondary xylem and phloem
C. possess conjunctive tissue between xylem and phloem
D. are not surrounded by pericycle

Answer

### Step-by-Step Solution:

1. **Understanding Vascular Bundles**:
- Vascular bundles are structures in plants that consist of xylem and phloem tissues. These tissues are essential for the transportation of water, nutrients, and food throughout the plant.

2. **Definition of Open Vascular Bundles**:
- Open vascular bundles are characterized by the presence of cambium between the xylem and phloem. Cambium is a type of meristematic tissue that has the ability to divide and produce new cells.

3. **Role of Cambium**:
- The cambium allows for the production of secondary xylem (wood) and secondary phloem (inner bark). This means that plants with open vascular bundles can grow in thickness over time.

4. **Comparison with Monocots**:
- In monocot plants, the vascular bundles are described as closed because they lack cambium. As a result, they do not have the capability to produce secondary xylem and phloem, and thus, they cannot grow in thickness.

5. **Conclusion**:
- Therefore, vascular bundles are described as open because they possess cambium, which enables the formation of secondary xylem and phloem, allowing for secondary growth in dicots.

### Final Answer:
Some vascular bundles are described as open because they possess cambium between the xylem and phloem, allowing them to produce secondary xylem and phloem.

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