The familiar sounds of your heart are made by the heart's valves as they open and close.
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Vampire bats have a natural anticoagulant in their saliva that permits continuous bleeding after they painlessly open a wound with their incisors. This capillary blood does not cause any significant blood loss to their victims.
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The average office desk has 400 times more bacteria on it than a toilet.
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Cancer has been around as long as humankind, but only in the second half of the twentieth century did the number of cancer cases explode.
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After 5 years of being diagnosed with rheumatoid arthritis, one every three patients will no longer be able to work.
The mammalian urinary system including the basic functional unit of the nephron.
Herbivores must overcome the wide variety of physical and chemical defences evolved by plants.