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There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
Cyanide works by making the human body unable to use oxygen.
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.
The horizontal fraction bar was introduced by the Arabs.
More than 34,000 trademarked medication names and more than 10,000 generic medication names are in use in the United States.
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