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Walt Disney helped combat malaria by making an animated film in 1943 called The Winged Scourge. This short film starred the seven dwarfs and taught children that mosquitos transmit malaria, which is a very bad disease. It advocated the killing of mosquitos to stop the disease.

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There are more nerve cells in one human brain than there are stars in the Milky Way.

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The heart is located in the center of the chest, with part of it tipped slightly so that it taps against the left side of the chest.

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

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Before a vaccine is licensed in the USA, the Food and Drug Administration (FDA) reviews it for safety and effectiveness. The CDC then reviews all studies again, as well as the American Academy of Pediatrics and the American Academy of Family Physicians. Every lot of vaccine is tested before administration to the public, and the FDA regularly inspects vaccine manufacturers' facilities.

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