|
|
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).
Of the estimated 2 million heroin users in the United States, 600,000–800,000 are considered hardcore addicts. Heroin addiction is considered to be one of the hardest addictions to recover from.
Sperm cells are so tiny that 400 to 500 million (400,000,000–500,000,000) of them fit onto 1 tsp.
The eye muscles are the most active muscles in the whole body. The external muscles that move the eyes are the strongest muscles in the human body for the job they have to do. They are 100 times more powerful than they need to be.
Asthma cases in Americans are about 75% higher today than they were in 1980.
![Bronfenbrenner’s model of the ecological-systems approach to studying development. He suggested that](https://biology-forums.com/gallery/47/medium_6_31_05_15_8_20_41_219701596.jpeg)
![This couple, a brother and sister in Germany and the proud parents of this child, are challenging ...](https://biology-forums.com/gallery/27/medium_482573_20_04_17_12_30_44_279421019.png)