List one difference between essential and non-essential amino acids.

Explanation

### Step-by-Step Solution:

1. **Definition of Amino Acids**: Amino acids are the building blocks of proteins, and there are 20 different amino acids that can combine in various ways to form proteins.

2. **Classification of Amino Acids**: Amino acids are classified into two categories: essential and non-essential amino acids.

3. **Essential Amino Acids**: Essential amino acids are those that cannot be synthesized by the body. This means that the cells of our body do not have the ability to produce these amino acids on their own. Therefore, we must obtain them from our diet. Examples of essential amino acids include lysine and leucine.

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