|
|
Sperm cells are so tiny that 400 to 500 million (400,000,000–500,000,000) of them fit onto 1 tsp.
The Romans did not use numerals to indicate fractions but instead used words to indicate parts of a whole.
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.
In most climates, 8 to 10 glasses of water per day is recommended for adults. The best indicator for adequate fluid intake is frequent, clear urination.
Your skin wrinkles if you stay in the bathtub a long time because the outermost layer of skin (which consists of dead keratin) swells when it absorbs water. It is tightly attached to the skin below it, so it compensates for the increased area by wrinkling. This happens to the hands and feet because they have the thickest layer of dead keratin cells.
![Several species of squirrels have melanistic phases. In large parts of United States and Canada, the](https://biology-forums.com/gallery/47/medium_27692_23_04_12_3_37_08.jpeg)
![Prevalence of Diabetes in the United States Based on Age and Sex Data from the American Diabetes ...](https://biology-forums.com/gallery/47/medium_667187_23_02_17_9_54_05_25735955.jpeg)