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Only 12 hours after an egg cell is fertilized by a sperm cell, the egg cell starts to divide. As it continues to divide, it moves along the fallopian tube toward the uterus at about 1 inch per day.
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.
Nearly 31 million adults in America have a total cholesterol level that is more than 240 mg per dL.
If all the neurons in the human body were lined up, they would stretch more than 600 miles.
Long-term mental and physical effects from substance abuse include: paranoia, psychosis, immune deficiencies, and organ damage.