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Your skin wrinkles if you stay in the bathtub a long time because the outermost layer of skin (which consists of dead keratin) swells when it absorbs water. It is tightly attached to the skin below it, so it compensates for the increased area by wrinkling. This happens to the hands and feet because they have the thickest layer of dead keratin cells.
This year, an estimated 1.4 million Americans will have a new or recurrent heart attack.
The first-known contraceptive was crocodile dung, used in Egypt in 2000 BC. Condoms were also reportedly used, made of animal bladders or intestines.
Asthma occurs in one in 11 children and in one in 12 adults. African Americans and Latinos have a higher risk for developing asthma than other groups.
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.