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Author Question: If 1.0 gram of an isotope has a half-life of 15 hours, the half-life of a 0.50 gram sample of the ... (Read 69 times) |
Though the United States has largely rejected the metric system, it is used for currency, as in 100 pennies = 1 dollar. Previously, the British currency system was used, with measurements such as 12 pence to the shilling, and 20 shillings to the pound.
Approximately 15–25% of recognized pregnancies end in miscarriage. However, many miscarriages often occur before a woman even knows she is pregnant.
On average, someone in the United States has a stroke about every 40 seconds. This is about 795,000 people per year.
More than 50% of American adults have oral herpes, which is commonly known as "cold sores" or "fever blisters." The herpes virus can be active on the skin surface without showing any signs or causing any symptoms.
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.