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Adult head lice are gray, about ? inch long, and often have a tiny dot on their backs. A female can lay between 50 and 150 eggs within the several weeks that she is alive. They feed on human blood.
Every 10 seconds, a person in the United States goes to the emergency room complaining of head pain. About 1.2 million visits are for acute migraine attacks.
The liver is the only organ that has the ability to regenerate itself after certain types of damage. As much as 25% of the liver can be removed, and it will still regenerate back to its original shape and size. However, the liver cannot regenerate after severe damage caused by alcohol.
Blood is approximately twice as thick as water because of the cells and other components found in it.
In 1864, the first barbiturate (barbituric acid) was synthesized.