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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.
Although puberty usually occurs in the early teenage years, the world's youngest parents were two Chinese children who had their first baby when they were 8 and 9 years of age.
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
The average human gut is home to perhaps 500 to 1,000 different species of bacteria.
Vaccines prevent between 2.5 and 4 million deaths every year.