older resin-clogged central seconedary xylem and younger outer secondary xylem are respectively known as

Options

A. Alburnm and duramen
B. Duramen and alburnum
C. Autumn wood and spiringwood
D. Springwood and autmn wood

Answer

To answer the question about the older resin-clogged central secondary xylem and the younger outer secondary xylem, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Secondary Xylem**:
- In dicotyledonous plants, secondary xylem is formed as a result of secondary growth, which occurs due to the activity of the vascular cambium.

2. **Identifying the Types of Secondary Xylem**:
- During the growing season, particularly in spring or early summer, the vascular cambium is active, producing a large amount of secondary xylem. This is referred to as **spring wood** or **early wood**.
- In contrast, during the autumn season, the conditions become less favorable for growth, resulting in the production of a smaller amount of secondary xylem, known as **autumn wood** or **late wood**.

3. **Distinguishing Between Older and Younger Xylem**:
- The older secondary xylem, which is located towards the center of the stem and may contain resin clogs, is referred to as **heartwood**.
- The younger secondary xylem, located towards the outer part of the stem, is referred to as **sapwood**.

4. **Correct Terminology**:
- The older resin-clogged central secondary xylem is known as **duramen** (or heartwood).
- The younger outer secondary xylem is known as **alburnum** (or sapwood).

5. **Final Answer**:
- Therefore, the correct answer to the question is that the older resin-clogged central secondary xylem is called **duramen**, and the younger outer secondary xylem is called **alburnum**.

### Conclusion:
- The answer to the question is **Option B: Duramen and Alburnum**.