The (A)_____ wood is lighter in colour and exhbit low density whereas (B)____ wood is darker in colour and exhibit high density.

Answer

To solve the question, we need to identify the types of wood based on their characteristics of color and density.

1. **Identify the characteristics of wood A**: The question states that wood A is lighter in color and exhibits low density. This description matches the type of wood known as "spring wood" or "early wood." Spring wood is formed during favorable growing conditions, typically in the spring, and is characterized by its lighter color and lower density.

2. **Identify the characteristics of wood B**: The question states that wood B is darker in color and exhibits high density. This description corresponds to "autumn wood" or "late wood." Autumn wood is formed during less favorable conditions, usually in the autumn, and is characterized by its darker color and higher density.

3. **Fill in the blanks**: Based on the identified types of wood:
- (A) Spring wood
- (B) Autumn wood

Thus, the complete sentence is: The (A) **spring wood** is lighter in color and exhibits low density whereas (B) **autumn wood** is darker in color and exhibits high density.