Which of these structures is not found in both a monocot root and a dicot stem ?

Options

A. pith
B. polyarch xylem
C. parenchymatous pericycle
D. multi layered parenchymatous cortex

Answer

To solve the question of which structure is not found in both a monocot root and a dicot stem, we can follow these steps:

### Step 1: Identify the structures mentioned
We need to analyze the structures provided in the question. The structures mentioned are:
- Pit
- Polyarch xylem
- Parenchymatous pericycle
- Multi-layer parenchymatous cortex

### Step 2: Analyze the presence of each structure
1. **Pit**: This structure is typically found in dicot stems but is not specifically mentioned for monocot roots.
2. **Polyarch xylem**: This structure is characteristic of monocot roots and is not found in dicot stems.
3. **Parenchymatous pericycle**: This structure is found in monocot roots but is not present in dicot stems, where sclerenchymatous pericycle is found instead.
4. **Multi-layer parenchymatous cortex**: This structure is present in both monocot roots and dicot stems.

### Step 3: Determine the structure not found in both
From the analysis:
- The **parenchymatous pericycle** is found in monocot roots but not in dicot stems.
- The **polyarch xylem** is found in monocot roots but not in dicot stems.
- The **pit** is found in dicot stems but not in monocot roots.
- The **multi-layer parenchymatous cortex** is found in both.

### Conclusion
The structure that is not found in both a monocot root and a dicot stem is the **parenchymatous pericycle**.

### Final Answer
**Parenchymatous pericycle** is the correct option that is not found in both a monocot root and a dicot stem.

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