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Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
Human stomach acid is strong enough to dissolve small pieces of metal such as razor blades or staples.
On average, the stomach produces 2 L of hydrochloric acid per day.
Human kidneys will clean about 1 million gallons of blood in an average lifetime.
When blood is exposed to air, it clots. Heparin allows the blood to come in direct contact with air without clotting.
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