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Cyanide works by making the human body unable to use oxygen.
The first-known contraceptive was crocodile dung, used in Egypt in 2000 BC. Condoms were also reportedly used, made of animal bladders or intestines.
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.
Essential fatty acids have been shown to be effective against ulcers, asthma, dental cavities, and skin disorders such as acne.
The average adult has about 21 square feet of skin.
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