A typical monocotyledonous root is characterised by

Options

A. usually more than six xylem bundles
B. Large and well develped pith
C. no secondary growth
D. all of these

Explanation

### Step-by-Step Solution

1. **Understanding Monocotyledonous Roots**:
- Monocotyledonous plants, or monocots, are characterized by having one cotyledon in their seeds. This trait extends to their root structure as well.

2. **Xylem Bundles**:
- A typical monocot root usually has more than six xylem bundles. This is a key distinguishing feature when compared to dicotyledonous roots, which typically have 2 to 4 xylem bundles.

3. **Development of Pith**:
- Monocot roots are known to have a large and well-developed pith. This is in contrast to many dicot roots, which may have a less developed pith.

4. **Secondary Growth**:
- Monocots do not exhibit secondary growth because they lack a vascular cambium. In dicots, the presence of cambium allows for secondary growth, leading to an increase in the thickness of the stem and roots.

5. **Conclusion**:
- Based on the above characteristics, a typical monocotyledonous root is characterized by:
- More than six xylem bundles.
- A large and well-developed pith.
- No secondary growth.

6. **Final Answer**:
- Therefore, the correct answer is "all of this" as all the mentioned characteristics are true for a typical monocotyledonous root.