Question 1
Question 2
Ask unlimited questions for free
There are 20 feet of blood vessels in each square inch of human skin.
The human body produces and destroys 15 million blood cells every second.
The first documented use of surgical anesthesia in the United States was in Connecticut in 1844.
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.
Long-term mental and physical effects from substance abuse include: paranoia, psychosis, immune deficiencies, and organ damage.
For a complete list of videos, visit our video library