How did railroads affect America's economy in the 1800's?

What period of history refers to the time when people did not have written records

Most sociologists agree that: a. culture is central in shaping gender roles, but only in preliterate societies. b. biological factors have some influence, but cultural factors are more important determinants of gender roles. c. biological factors are influential in determining gender roles, but only in industrial or complex societies. d. biological factors only explain differences between men and women with regard to aggression and disease. e. there is no difference between the influences of culture or biology on the development of gender roles, as they are unpredictable.

How has congress added to the president’s role as chief economic planner over the years?