P-protein occurs in
(a) Sieve tube elements
(b) Tracheids
(c) Vessels
(d) Phloem parenchyma

Options

A. Sieve tube elements
B. Tracheids
C. Vessels
D. Phloem parchyma

Answer

**Step-by-Step Solution:**

1. **Understanding P-proteins**: P-proteins are known as phloem-specific proteins. They play a crucial role in the functioning of the phloem tissue in plants.

2. **Identifying the location of P-proteins**: P-proteins are primarily found in sieve tube elements, which are specialized cells in the phloem responsible for the transport of nutrients.

3. **Examining the options**:
- (a) Sieve tube elements: This is where P-proteins are found.
- (b) Tracheids: These are involved in water transport and do not contain P-proteins.
- (c) Vessels: Similar to tracheids, vessels are part of the xylem and do not contain P-proteins.
- (d) Phloem parenchyma: While they are part of the phloem, they do not specifically contain P-proteins.

4. **Conclusion**: Based on the understanding that P-proteins are specific to sieve tube elements, the correct answer is (a) Sieve tube elements.

**Final Answer**: (a) Sieve tube elements

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