Fibres are likely to be absent in a) primary phloem b) secondary phloem

Options

A. secondary phloem
B. secondary xylem
C. primary phloem
D. leaves

Explanation

To solve the question regarding the presence of fibers in primary and secondary phloem, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Phloem Types**:
- Phloem is a type of vascular tissue in plants responsible for the transport of nutrients, particularly sugars produced by photosynthesis.
- There are two main types of phloem: primary phloem and secondary phloem.

2. **Primary Phloem**:
- Primary phloem is formed from the apical meristem during the initial growth of the plant.
- It consists of two parts: proto-phloem and meta-phloem.
- Notably, primary phloem does not contain fibers. Instead, it mainly consists of sieve elements and companion cells.

3. **Secondary Phloem**:
- Secondary phloem is produced by the vascular cambium during secondary growth, which occurs in woody plants.
- Secondary phloem often contains fibers, which provide additional support and strength to the plant structure.

4. **Conclusion**:
- Based on the above information, we can conclude that fibers are likely to be absent in primary phloem (option a), while they are present in secondary phloem (option b).

### Final Answer:
The correct answer is **a) primary phloem**.

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