Why can a pace or a footstep not be used as a standard unit of length?

Explanation

### Step-by-Step Solution:

1. **Understanding Standard Units of Length**:
- A standard unit of length is a fixed measurement that everyone can agree upon. For example, the centimeter (cm) or meter (m) is standardized so that if one person measures an object and says it is 5 cm long, anyone else measuring that same object should also find it to be 5 cm.

2. **Measuring with Footsteps or Paces**:
- When we measure distance using footsteps or paces, the measurement can vary significantly from one person to another. For instance, one person might have a larger foot and take longer steps, while another person might have smaller feet and take shorter steps.

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