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Did you know?
The first-known contraceptive was crocodile dung, used in Egypt in 2000 BC. Condoms were also reportedly used, made of animal bladders or intestines.
Did you know?
Normal urine is sterile. It contains fluids, salts, and waste products. It is free of bacteria, viruses, and fungi.
Did you know?
Cyanide works by making the human body unable to use oxygen.
Did you know?
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
Did you know?
Intradermal injections are somewhat difficult to correctly administer because the skin layers are so thin that it is easy to accidentally punch through to the deeper subcutaneous layer.