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Did you know?
The heart is located in the center of the chest, with part of it tipped slightly so that it taps against the left side of the chest.
Did you know?
Vaccines prevent between 2.5 and 4 million deaths every year.
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?
About one in five American adults and teenagers have had a genital herpes infection—and most of them don't know it. People with genital herpes have at least twice the risk of becoming infected with HIV if exposed to it than those people who do not have genital herpes.
Did you know?
There are approximately 3 million unintended pregnancies in the United States each year.