Give the function of heparin .

Explanation

### Step-by-Step Solution:

1. **Definition of Heparin**: Heparin is a naturally occurring molecule in the body, specifically classified as a glycosaminoglycan.

2. **Primary Function**: The main function of heparin is to act as an anticoagulant. This means it prevents the blood from clotting.

3. **Mechanism of Action**: Heparin works by inhibiting the formation of blood clots. It not only prevents new clots from forming but also stops existing clots from growing larger.

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