According to anthropologists, why did planting crops lead to the rise of a political class? With economic stability came the need for warriors. The more settled a community was the more they needed a form of monetary exchange. As food became more plentiful, people were freed up to serve as community leaders. The crops planted could be used to trade with other cultures. As settlements developed, leaders emerged to help organize and regulate these budding civilizations.

According to the federal regulations, which of the following studies meets the definition of research with human subjects? a. a researcher uses the customs office’s passenger lists for ships bringing immigrants to the us between 1820-1845 to track the numbers of immigrants from certain ethnic groups. b. a researcher conducts a linguistic study of comments posted on a local public blog. c. a developmental psychologist videotapes interactions between groups of toddlers and their care givers to determine which intervention methods most effectively manage aggression. d. a researcher asks the director of a local free clinic about the number of patients in the last two years with newly diagnosed hiv/aids.