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 most destructive flu epidemic of all times in recorded history occurred in 1918, with approximately 20 million deaths worldwide.
After a vasectomy, it takes about 12 ejaculations to clear out sperm that were already beyond the blocked area.
If you could remove all of your skin, it would weigh up to 5 pounds.
Thyroid conditions may make getting pregnant impossible.
For a complete list of videos, visit our video library