Companion cells are usually associated with

Options

A. Fibres
B. Trcheids
C. Vessels
D. Sieve tube

Answer

### Step-by-Step Solution:

1. **Identify the Role of Companion Cells**: Companion cells are specialized cells found in the phloem tissue of flowering plants. They play a crucial role in the transport of nutrients, particularly sugars.

2. **Understand the Structure of Phloem**: Phloem is composed of various cell types, including sieve tube elements (C-tubes) and companion cells. The sieve tube elements are responsible for the conduction of food, while companion cells assist in this process.

3. **Relationship Between Companion Cells and Sieve Tube Elements**: Companion cells are closely associated with sieve tube elements. They help in the maintenance and functioning of the sieve tubes by providing metabolic support.

4. **Note the Absence in Gymnosperms**: It is important to note that companion cells are typically absent in gymnosperms, which are a group of seed-producing plants that includes conifers.

5. **Conclude the Association**: Based on the above points, it can be concluded that companion cells are usually associated with sieve tube elements (C-tubes) in the phloem of flowering plants.

### Final Answer:
Companion cells are usually associated with **sieve tube elements (C-tubes)**.

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