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Did you know?
Vaccines cause herd immunity. If the majority of people in a community have been vaccinated against a disease, an unvaccinated person is less likely to get the disease since others are less likely to become sick from it and spread the disease.
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?
Human stomach acid is strong enough to dissolve small pieces of metal such as razor blades or staples.
Did you know?
Human kidneys will clean about 1 million gallons of blood in an average lifetime.
Did you know?
The horizontal fraction bar was introduced by the Arabs.