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The Babylonians wrote numbers in a system that used 60 as the base value rather than the number 10. They did not have a symbol for "zero."
Malaria was not eliminated in the United States until 1951. The term eliminated means that no new cases arise in a country for 3 years.
There are more sensory neurons in the tongue than in any other part of the body.
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.
Signs of depression include feeling sad most of the time for 2 weeks or longer; loss of interest in things normally enjoyed; lack of energy; sleep and appetite disturbances; weight changes; feelings of hopelessness, helplessness, or worthlessness; an inability to make decisions; and thoughts of death and suicide.