A sequence of three nitrogen bases that code for an amino acid is a ..................

Explanation

**Step-by-Step Solution:**

1. **Understanding the Basics**:
- DNA is made up of units called nucleotides. Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base.

2. **Transcription and Translation**:
- The process of synthesizing RNA from DNA is called transcription.
- The process of synthesizing proteins from RNA is called translation.
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