Sperm cells are so tiny that 400 to 500 million (400,000,000–500,000,000) of them fit onto 1 tsp.
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Thyroid conditions cause a higher risk of fibromyalgia and chronic fatigue syndrome.
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The first documented use of surgical anesthesia in the United States was in Connecticut in 1844.
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The human body produces and destroys 15 million blood cells every second.
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The highest suicide rate in the United States is among people ages 65 years and older. Almost 15% of people in this age group commit suicide every year.
A molecular model showing chromosome territories in the cell nucleus of humans
Prenatal development in humans.
Photograph of the flea that transmits Yersinia pestis to cause bubonic plague, called the oriental r
Effects of Estradiol and Testosterone on Interfemale Aggression in Rats (Based on data from van de P
Historical Time Line of Regulatory Acts, Standards, and Organizations