Ask unlimited questions for free
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
There are more sensory neurons in the tongue than in any other part of the body.
The B-complex vitamins and vitamin C are not stored in the body and must be replaced each day.
Aspirin is the most widely used drug in the world. It has even been recognized as such by the Guinness Book of World Records.
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