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Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
People who have myopia, or nearsightedness, are not able to see objects at a distance but only up close. It occurs when the cornea is either curved too steeply, the eye is too long, or both. This condition is progressive and worsens with time. More than 100 million people in the United States are nearsighted, but only 20% of those are born with the condition. Diet, eye exercise, drug therapy, and corrective lenses can all help manage nearsightedness.
The word drug comes from the Dutch word droog (meaning "dry"). For centuries, most drugs came from dried plants, hence the name.
Human stomach acid is strong enough to dissolve small pieces of metal such as razor blades or staples.
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.