The commercial jute fibres are obtained from
(a) Primary phloem
(b) Secondary pholem
(c) Secondary xylem
(d) Primary xylem

Options

A. Primary phloem
B. Secondary pholem
C. Secondary xylem
D. Primary xylem

Answer

To solve the question regarding the source of commercial jute fibers, follow these steps:

1. **Identify the Plant Species**: Understand that commercial jute fibers are derived from two main species, *Corchorus capsularis* and *Corchorus olitorius*.

2. **Understand Fiber Source**: Recognize that jute fibers are specifically obtained from the phloem tissue of the plants. Phloem is responsible for the transport of nutrients and is also known as bast in some contexts.

3. **Differentiate Between Phloem Types**: There are two types of phloem: primary phloem and secondary phloem. The fibers used for jute production come from the secondary phloem, which is formed later in the plant's growth.

4. **Evaluate the Options**:
- (a) Primary phloem: Incorrect, as jute fibers are not sourced from primary phloem.
- (b) Secondary phloem: Correct, as jute fibers are obtained from secondary phloem.
- (c) Secondary xylem: Incorrect, as jute fibers do not come from xylem.
- (d) Primary xylem: Incorrect, as jute fibers are not sourced from xylem.

5. **Conclusion**: Based on the above analysis, the correct answer is (b) Secondary phloem.