Ask unlimited questions for free
The familiar sounds of your heart are made by the heart's valves as they open and close.
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 FDA recognizes 118 routes of administration.
The average adult has about 21 square feet of skin.
More than nineteen million Americans carry the factor V gene that causes blood clots, pulmonary embolism, and heart disease.
For a complete list of videos, visit our video library