Polyarch and exarch condition is found in
(a) monocot stem
(b) monocot root
(c) dicot stem
(d) dicot root

Options

A. monocot stem
B. monocot root
C. dicot stem
D. dicot root

Answer

To determine where the polyarch and exarch conditions are found, let's analyze each option step by step:

### Step-by-Step Solution:

1. **Understanding Polyarch Condition**:
- Polyarch condition refers to the presence of multiple vascular bundles. This is typically seen in certain plant structures where there are many vascular strands.

2. **Understanding Exarch Condition**:
- Exarch condition describes the arrangement of xylem where the protoxylem (the first xylem to develop) is located towards the periphery, and the metaxylem (the later-formed xylem) is located towards the center.

3. **Analyzing Option (a): Monocot Stem**:
- Monocot stems have multiple vascular bundles (often around 8), which indicates a polyarch condition.
- The xylem in monocot stems is arranged in an exarch condition.
- **Conclusion**: Monocot stem exhibits both polyarch and exarch conditions.

4. **Analyzing Option (b): Monocot Root**:
- Monocot roots also have multiple vascular bundles, suggesting a polyarch condition.
- However, the xylem is arranged in an endarch condition, not exarch.
- **Conclusion**: Monocot root does not exhibit exarch condition.

5. **Analyzing Option (c): Dicot Stem**:
- Dicot stems typically have fewer vascular bundles, arranged in a conjoined collateral and open form.
- The xylem is arranged in an endarch condition.
- **Conclusion**: Dicot stem does not exhibit polyarch or exarch conditions.

6. **Analyzing Option (d): Dicot Root**:
- Dicot roots have a tetrarch arrangement of vascular bundles, which is not polyarch.
- The xylem is arranged in an exarch condition, but since it is not polyarch, this option is also incorrect.
- **Conclusion**: Dicot root does not exhibit polyarch condition.

### Final Answer:
The correct answer is **(a) monocot stem**.

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