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If all the neurons in the human body were lined up, they would stretch more than 600 miles.
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.
The familiar sounds of your heart are made by the heart's valves as they open and close.
Pubic lice (crabs) are usually spread through sexual contact. You cannot catch them by using a public toilet.
Calcitonin is a naturally occurring hormone. In women who are at least 5 years beyond menopause, it slows bone loss and increases spinal bone density.
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