|
|
The horizontal fraction bar was introduced by the Arabs.
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.
There used to be a metric calendar, as well as metric clocks. The metric calendar, or "French Republican Calendar" divided the year into 12 months, but each month was divided into three 10-day weeks. Each day had 10 decimal hours. Each hour had 100 decimal minutes. Due to lack of popularity, the metric clocks and calendars were ended in 1795, three years after they had been first marketed.
Many of the drugs used by neuroscientists are derived from toxic plants and venomous animals (such as snakes, spiders, snails, and puffer fish).