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The horizontal fraction bar was introduced by the Arabs.
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
Certain chemicals, after ingestion, can be converted by the body into cyanide. Most of these chemicals have been removed from the market, but some old nail polish remover, solvents, and plastics manufacturing solutions can contain these substances.
Acute bronchitis is an inflammation of the breathing tubes (bronchi), which causes increased mucus production and other changes. It is usually caused by bacteria or viruses, can be serious in people who have pulmonary or cardiac diseases, and can lead to pneumonia.