outer lighter coloured/alburnum region of wood is

Options

A. autumn wood
B. spring wood
C. heart wood
D. sapwood

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the outer lighter colored region of wood, which is known as the alburnum.

2. **Identifying the Options**: The options provided are:
- Autumn wood
- Spring wood
- Heartwood
- Sapwood

3. **Defining the Terms**:
- **Autumn Wood**: This refers to the small amount of secondary xylem produced during the autumn season.
- **Spring Wood**: This is the large amount of secondary xylem formed during the spring season.
- **Heartwood**: This is the inner, darker colored, non-functional secondary xylem, often referred to as hardwood.
- **Sapwood (Alburnum)**: This is the outer, lighter colored, functional secondary xylem.

4. **Analyzing the Options**:
- Since the question specifies the outer lighter colored region, we can eliminate heartwood, which is darker and non-functional.
- Autumn wood and spring wood refer to seasonal growth patterns and do not describe the outer region of wood.

5. **Conclusion**: The correct answer is **Sapwood**, as it is the outer lighter colored functional secondary xylem.

**Final Answer**: The outer lighter colored/alburnum region of wood is **Sapwood**.

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