|
|
Liver spots have nothing whatsoever to do with the liver. They are a type of freckles commonly seen in older adults who have been out in the sun without sufficient sunscreen.
Hippocrates noted that blood separates into four differently colored liquids when removed from the body and examined: a pure red liquid mixed with white liquid material with a yellow-colored froth at the top and a black substance that settles underneath; he named these the four humors (for blood, phlegm, yellow bile, and black bile).
In the United States, there is a birth every 8 seconds, according to the U.S. Census Bureau's Population Clock.
Human neurons are so small that they require a microscope in order to be seen. However, some neurons can be up to 3 feet long, such as those that extend from the spinal cord to the toes.
Sperm cells are so tiny that 400 to 500 million (400,000,000–500,000,000) of them fit onto 1 tsp.