The fundamental building block of proteins is ........

Explanation

To answer the question, "The fundamental building block of proteins is ........", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Proteins**:
- Proteins are essential biomolecules that play various roles in the body, including structural, functional, and regulatory roles.
- They are polymers, meaning they are made up of smaller repeating units.

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