What does a gene contain?

Explanation

### Step-by-Step Solution

1. **Definition of a Gene**: A gene is a small section of DNA. It is a fundamental unit of heredity in living organisms.

2. **Function of a Gene**: The primary function of a gene is to instruct the synthesis of specific molecules, usually proteins. These proteins play crucial roles in the body.

3. **Example of Gene Function**: For instance, a gene responsible for hair color will provide instructions for producing the protein that determines the color of your hair, such as black.

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