If protoxylem lies towards the centre (pith) and the metaxylem lies towards the periphery of the organ, then this type of primary xylem is called :-

Options

A. Exarch
B. Endarch
C. Mesarch
D. Polyarch

Answer

To solve the question regarding the arrangement of protoxylem and metaxylem in primary xylem, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definitions**:
- **Protoxylem**: This is the first formed xylem tissue that develops during the growth of the plant.
- **Metaxylem**: This is the later formed xylem tissue that develops after protoxylem.

2. **Identify the Arrangement**:
- The question states that protoxylem is located towards the center (pith) of the organ, while metaxylem is located towards the periphery.

3. **Recall the Types of Xylem Arrangements**:
- There are two main arrangements of xylem:
- **Endarch**: In this arrangement, the protoxylem is located towards the center, and the metaxylem is towards the periphery.
- **Exarch**: In this arrangement, the protoxylem is located towards the periphery, and the metaxylem is towards the center.

4. **Match the Given Arrangement with Definitions**:
- Since the question specifies that protoxylem is towards the center and metaxylem is towards the periphery, this matches the definition of **endarch**.

5. **Conclusion**:
- Therefore, the type of primary xylem described in the question, where protoxylem is towards the center and metaxylem is towards the periphery, is called **endarch**.

### Final Answer:
The type of primary xylem is called **endarch**.

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