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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.
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
On average, someone in the United States has a stroke about every 40 seconds. This is about 795,000 people per year.
According to the American College of Allergy, Asthma & Immunology, more than 50 million Americans have some kind of food allergy. Food allergies affect between 4 and 6% of children, and 4% of adults, according to the CDC. The most common food allergies include shellfish, peanuts, walnuts, fish, eggs, milk, and soy.
The horizontal fraction bar was introduced by the Arabs.