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The first-known contraceptive was crocodile dung, used in Egypt in 2000 BC. Condoms were also reportedly used, made of animal bladders or intestines.
Human stomach acid is strong enough to dissolve small pieces of metal such as razor blades or staples.
There are more nerve cells in one human brain than there are stars in the Milky Way.
Excessive alcohol use costs the country approximately $235 billion every year.
There are 60,000 miles of blood vessels in every adult human.
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