Ask unlimited questions for free
In the United States, there is a birth every 8 seconds, according to the U.S. Census Bureau's Population Clock.
The word drug comes from the Dutch word droog (meaning "dry"). For centuries, most drugs came from dried plants, hence the name.
The average human gut is home to perhaps 500 to 1,000 different species of bacteria.
The Babylonians wrote numbers in a system that used 60 as the base value rather than the number 10. They did not have a symbol for "zero."
The most destructive flu epidemic of all times in recorded history occurred in 1918, with approximately 20 million deaths worldwide.
For a complete list of videos, visit our video library