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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.

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The term bacteria was devised in the 19th century by German biologist Ferdinand Cohn. He based it on the Greek word "bakterion" meaning a small rod or staff. Cohn is considered to be the father of modern bacteriology.

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It is believed that the Incas used anesthesia. Evidence supports the theory that shamans chewed cocoa leaves and drilled holes into the heads of patients (letting evil spirits escape), spitting into the wounds they made. The mixture of cocaine, saliva, and resin numbed the site enough to allow hours of drilling.

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The immune system needs 9.5 hours of sleep in total darkness to recharge completely.

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Opium has influenced much of the world's most popular literature. The following authors were all opium users, of varying degrees: Lewis Carroll, Charles, Dickens, Arthur Conan Doyle, and Oscar Wilde.

Structure of a DNA polymerase polypeptide that contains a 3'–5' proofread Structure of a DNA polymerase polypeptide that contains a 3'–5' proofread
Steps in sequencing a polypeptide Steps in sequencing a polypeptide
The β conformation of polypeptide chains The β conformation of polypeptide chains
Action of Steroid Hormones Action of Steroid Hormones
Carbohydrates: Sugars, Starches, and Fiber Carbohydrates: Sugars, Starches, and Fiber
Structure of polypeptide chains Structure of polypeptide chains
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