in dicot stem, xylem is

Options

A. polyarch
B. monoarch
C. endarch
D. exarch

Answer

### Step-by-Step Solution:

1. **Understand the Question**: The question asks about the arrangement of xylem in a dicot stem. We need to identify the correct term that describes this arrangement.

2. **Know the Functions of Xylem**: Xylem has two primary functions:
- It stores nutrients.
- It transports nutrients and water throughout the plant.

3. **Identify the Types of Xylem Arrangement**: In dicot stems, the arrangement of xylem can be classified into different types:
- Polyarc
- Monoarc
- Endarc
- Exarc

4. **Define Endarch**: In an endarch arrangement, the protoxylem (the first-formed xylem) is located towards the center of the stem, while the metaxylem (the later-formed xylem) is located towards the periphery.

5. **Differentiate Between Options**:
- **Polyarc**: This arrangement is typically found in monocots, not dicots, and involves multiple vascular bundles.
- **Monoarc**: This arrangement has only one xylem and is also characteristic of monocots.
- **Endarc**: This is the correct arrangement for dicot stems where the protoxylem is centrally located.
- **Exarc**: This arrangement is associated with roots, not stems, and is therefore not applicable here.

6. **Conclusion**: Based on the definitions and characteristics discussed, the correct answer is that in a dicot stem, xylem is **endarch**.

### Final Answer:
In dicot stem, xylem is **endarch**.

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