oldest xylem is

Options

A. on the outside of xylem
B. in the centre
C. in the heartwood
D. in the sapwood.

Answer

To answer the question "Where is the oldest xylem found?", we can break down the solution step by step:

### Step-by-Step Solution:

1. **Understanding Xylem**:
- Xylem is a type of tissue in vascular plants responsible for the transport of water and nutrients from the roots to the rest of the plant. It also provides structural support.

2. **Identifying Types of Xylem**:
- There are two types of xylem: primary xylem and secondary xylem. The primary xylem is formed during the first growth of the plant, while secondary xylem is formed later as the plant matures.

3. **Location of Oldest Xylem**:
- The oldest xylem refers to the primary xylem, which is typically located at the center of the stem.

4. **Role of Pith**:
- The pith is the central part of the stem. Over time, as the plant grows, the pith may be destroyed or replaced by the oldest xylem, which is the primary xylem.

5. **Conclusion**:
- Therefore, the oldest xylem is found in the center of the stem, specifically in the pith area.

### Final Answer:
The oldest xylem is found in the center of the stem (in the pith).

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