which is not true of dicot root

Options

A. vascular bundles 15-20
B. radial vascular bundles
C. secondary growth
D. pith little or absent

Answer

To determine which statement is not true about dicot roots, we will analyze the given statements step by step.

### Step-by-Step Solution:

1. **Understanding Dicot Roots**:
- Dicot roots typically have a specific structure that includes a central vascular cylinder, which is surrounded by a cortex and an outer epidermis.

2. **Analyzing the Statements**:
- **Statement 1**: "Vascular bundles from 15 to 20" - This statement is likely referring to the number of vascular bundles in dicot roots. Dicot roots usually have a smaller number of vascular bundles, typically less than 10, so this statement is likely not true.
- **Statement 2**: "Radial vascular bundles" - This statement is true. Dicot roots have radial vascular bundles, where xylem and phloem are arranged in a radial pattern.
- **Statement 3**: "Secondary growth" - This statement is true. Dicot roots can undergo secondary growth due to the presence of cambium, which allows for the increase in thickness.
- **Statement 4**: "Pith little or absent" - This statement is also true. In many dicot roots, the pith is either very small or absent.

3. **Identifying the Incorrect Statement**:
- Based on the analysis, the first statement regarding the number of vascular bundles (15 to 20) is not true for dicot roots.

### Conclusion:
The statement that is not true of dicot roots is **"Vascular bundles from 15 to 20."**

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