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Blood in the urine can be a sign of a kidney stone, glomerulonephritis, or other kidney problems.
Illicit drug use costs the United States approximately $181 billion every year.
For about 100 years, scientists thought that peptic ulcers were caused by stress, spicy food, and alcohol. Later, researchers added stomach acid to the list of causes and began treating ulcers with antacids. Now it is known that peptic ulcers are predominantly caused by Helicobacter pylori, a spiral-shaped bacterium that normally exist in the stomach.
The horizontal fraction bar was introduced by the Arabs.
The lipid bilayer is made of phospholipids. They are arranged in a double layer because one of their ends is attracted to water while the other is repelled by water.