The chief function of sieve tubes is

Options

A. (a) To translocate the organic materials manufactured in the leaves
B. (b) To conduct minerals
C. (c) To transport water from root to leaves
D. (d) To help to plant in forming wood

Answer

**Step-by-Step Solution:**

1. **Understanding Sieve Tubes**: Sieve tubes, also known as sieve tube elements, are specialized elongated living cells found in the phloem tissue of flowering plants.

2. **Function of Sieve Tubes**: The primary function of sieve tubes is to transport organic materials, particularly sugars, throughout the plant. This process is crucial for the distribution of energy produced during photosynthesis.

3. **Role of Companion Cells**: Companion cells are closely associated with sieve tubes and play a supportive role in the transport process. They help in loading and unloading sugars into and out of the sieve tubes.

4. **Structure of Sieve Tubes**: Sieve tubes have sieve plates that facilitate the movement of sap (which contains sugars) from one sieve tube element to another, ensuring efficient transport.

5. **Analyzing the Options**:
- **Option A**: "To translocate the organic material manufactured in the leaves." This is correct as it refers to the transport of sugars produced during photosynthesis.
- **Option B**: "To conduct minerals." This is incorrect; mineral transport is primarily the function of xylem.
- **Option C**: "To transport water from roots to leaves." This is also incorrect; this function is again mediated by xylem.
- **Option D**: "To help the plant in forming wood." This is incorrect as well; wood formation is not a function of sieve tubes.

6. **Conclusion**: The most appropriate answer is **Option A**, as it accurately describes the chief function of sieve tubes in transporting sugars from the leaves to other parts of the plant.

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