Ask unlimited questions for free
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
The first war in which wide-scale use of anesthetics occurred was the Civil War, and 80% of all wounds were in the extremities.
You should not take more than 1,000 mg of vitamin E per day. Doses above this amount increase the risk of bleeding problems that can lead to a stroke.
Blood in the urine can be a sign of a kidney stone, glomerulonephritis, or other kidney problems.
The Romans did not use numerals to indicate fractions but instead used words to indicate parts of a whole.
For a complete list of videos, visit our video library