Why do we go for an atomic standard for defining metre and second?

Explanation

To understand why we use atomic standards for defining the meter and the second, we can break down the reasoning into several steps:

### Step-by-Step Solution

1. **Understanding Measurement Standards**:
- Measurement standards are essential for consistency and accuracy in scientific measurements. They provide a reference point that can be universally accepted and replicated.

2. **Historical Context**:
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