Up to then, scientists divided the living world into two kingdoms according to genetic packaging.
Political scientists and historians have divided the development of America's two-party system into five eras.
Lab staff and visiting scientists had divided into camps.
The scientists divided 25 smokers into two groups.
The scientists divided the 48 beagles, ages 8 to 11, into four groups, giving them an enriched diet, an enriched environment, neither or both.
The scientists randomly divided 60 patients ages 26 to 64, all of them receiving traditional pain treatment, into three groups.
The scientists randomly divided 60 healthy men and women into two groups.
The scientist divides his time between Yale University and Fudan University in Shanghai, and works as an investigator for the Howard Hughes Medical Institute.
In a trial published online Dec. 21 in The Archives of Disease in Childhood: Fetal and Neonatal Edition, scientists divided 98 women into two groups.
In an attempt to organize the volcanoes by age, scientists typically divide them into two provinces: the High Cascades-the younger volcanoes-and the Western Cascades, comprising the older volcanoes.