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If you could remove all of your skin, it would weigh up to 5 pounds.
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
Sperm cells are so tiny that 400 to 500 million (400,000,000–500,000,000) of them fit onto 1 tsp.
Blood is approximately twice as thick as water because of the cells and other components found in it.
Aspirin may benefit 11 different cancers, including those of the colon, pancreas, lungs, prostate, breasts, and leukemia.
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