Shark corneas are used in eye transplants and shark bone marrow can be used to graft human bones.
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Research has determined that most people are happiest at 7:26pm on a Saturday night.
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Only 12,000 years ago there was a species closely related to modern humans called Homo floresiensis that had been living on an Indonesian Island. They used fire and rather advanced tools, yet were only about 3 feet tall and weighed around 25kg.
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An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
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Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
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It takes about 20 seconds for a red blood cell to circle the whole body.
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Blue eyes are a genetic mutation. Before the mutation occured, all humans had brown eyes.
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After age 30, the brain shrinks a quarter of a percent (0.25%) in mass each year.
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