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Did you know?
The horizontal fraction bar was introduced by the Arabs.
Did you know?
Autoimmune diseases occur when the immune system destroys its own healthy tissues. When this occurs, white blood cells cannot distinguish between pathogens and normal cells.
Did you know?
When blood is exposed to air, it clots. Heparin allows the blood to come in direct contact with air without clotting.
Did you know?
Glaucoma is a leading cause of blindness. As of yet, there is no cure. Everyone is at risk, and there may be no warning signs. It is six to eight times more common in African Americans than in whites. The best and most effective way to detect glaucoma is to receive a dilated eye examination.
Did you know?
After a vasectomy, it takes about 12 ejaculations to clear out sperm that were already beyond the blocked area.