The basic difference between stem and root is that xylum in stem is -

Options

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

Answer

To answer the question regarding the basic difference between stem and root in terms of the arrangement of xylem, we can break down the solution into the following steps:

### Step-by-Step Solution:

1. **Understanding Xylem Arrangement**:
- Xylem is a type of vascular tissue responsible for the transport of water and nutrients in plants. The arrangement of xylem can vary between stems and roots.

2. **Identify the Types of Xylem Arrangement**:
- The terms used to describe xylem arrangement include:
- **Endarch**: Where the protoxylem (the first-formed xylem) is located towards the inside and metaxylem (the later-formed xylem) is towards the outside.
- **Exarch**: Where the protoxylem is located towards the outside and metaxylem is towards the inside.
- **Mesarch**: A less common arrangement where protoxylem and metaxylem are intermixed.
- **Polyarch**: Refers to a condition with multiple protoxylem strands.

3. **Xylem Arrangement in Stems**:
- In stems, the xylem is arranged in an **endarch** condition. This means that the protoxylem is located towards the center and the metaxylem is located towards the outer side.

4. **Xylem Arrangement in Roots**:
- In roots, the xylem is arranged in an **exarch** condition. Here, the protoxylem is located towards the outer side and the metaxylem is located towards the center.

5. **Conclusion**:
- Therefore, the basic difference between the stem and root in terms of xylem arrangement is that the xylem in the stem is **endarch**, while in the root it is **exarch**.

### Final Answer:
The basic difference between stem and root is that xylem in stem is **endarch**.