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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."
Sperm cells are so tiny that 400 to 500 million (400,000,000–500,000,000) of them fit onto 1 tsp.
Immunoglobulin injections may give short-term protection against, or reduce severity of certain diseases. They help people who have an inherited problem making their own antibodies, or those who are having certain types of cancer treatments.
Approximately one in three babies in the United States is now delivered by cesarean section. The number of cesarean sections in the United States has risen 46% since 1996.
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.