when one wood is lighter in colour with lower density, the other wood is darker with higher density. They are

Options

A. springwood and autumn- wood
B. heartwood and late wood
C. springwood and early wood
D. autumn wood and springwood.

Answer

### Step-by-Step Solution:

1. **Understanding Wood Types**: The question describes two types of wood based on their color and density. One is lighter in color and lower in density, while the other is darker and has higher density.

2. **Identifying the Growth Seasons**: In temperate regions, the growth of wood is influenced by seasonal changes. The cambium layer, responsible for wood formation, is more active in spring than in autumn.

3. **Early Wood Formation**: During the spring, the cambium is highly active, leading to the formation of what is known as "early wood" or "spring wood." This wood has larger xylem elements and wider cavities, resulting in a lighter color and lower density.

4. **Late Wood Formation**: In contrast, during the autumn, the cambium activity decreases, leading to the formation of "late wood" or "autumn wood." This wood has smaller xylem elements and narrower cavities, resulting in a darker color and higher density.

5. **Conclusion**: Based on the characteristics described, the two types of wood are:
- **Early Wood (Spring Wood)**: Lighter in color, lower density.
- **Late Wood (Autumn Wood)**: Darker in color, higher density.

### Final Answer:
The two types of wood are **Early Wood (Spring Wood)** and **Late Wood (Autumn Wood)**.

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