A common character of monocot and dicot roots is

Options

A. exarch protoxylem
B. number of xylem strands
C. endarchprotexylem
D. occurrence of secondary growth

Answer

To answer the question "A common character of monocot and dicot roots is," we need to analyze the options provided and identify the correct answer based on the anatomical features of monocot and dicot roots.

### Step-by-Step Solution:

1. **Understand the Options**:
- Option A: Exarch protoxylem
- Option B: Number of xylem strands
- Option C: Endarch protoxylem
- Option D: Occurrence of secondary growth

2. **Analyze the Characteristics of Monocot and Dicot Roots**:
- Monocot roots typically have an exarch arrangement of protoxylem, where the protoxylem is located towards the outside of the xylem.
- Dicot roots usually have an endarch arrangement of protoxylem, where the protoxylem is located towards the inside of the xylem.
- Both types of roots have a single-layered epidermis and a single-layered endodermis.

3. **Identifying Common Features**:
- The presence of exarch protoxylem is a common feature in both monocots and dicots, despite the differences in their vascular arrangements.
- The number of xylem strands can vary between monocots and dicots, so this is not a common character.
- Endarch protoxylem is specific to dicots, so it cannot be a common feature.
- Secondary growth is typically absent in monocots and present in many dicots, making it not a common feature.

4. **Conclusion**:
- Based on the analysis, the correct answer is **Option A: Exarch protoxylem**. This is a common character found in both monocot and dicot roots.

### Final Answer:
**A common character of monocot and dicot roots is Exarch protoxylem.**