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Did you know?
The familiar sounds of your heart are made by the heart's valves as they open and close.
Did you know?
People about to have surgery must tell their health care providers about all supplements they take.
Did you know?
Pubic lice (crabs) are usually spread through sexual contact. You cannot catch them by using a public toilet.
Did you know?
Sperm cells are so tiny that 400 to 500 million (400,000,000–500,000,000) of them fit onto 1 tsp.
Did you know?
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.