Ask unlimited questions for free
If all the neurons in the human body were lined up, they would stretch more than 600 miles.
When blood is exposed to air, it clots. Heparin allows the blood to come in direct contact with air without clotting.
Excessive alcohol use costs the country approximately $235 billion every year.
Thyroid conditions may make getting pregnant impossible.
Your heart beats over 36 million times a year.
For a complete list of videos, visit our video library