Supply and Demand {Ans: relationship between the amount of product and the desire for the product}Bias {Ans: preference in favor of or against one thing, person, or group compared with another, usually in a way considered to be unfair.}Surplus {Ans: extra}Primary Source {Ans: A document or physical object which was written or created during the time under study.}Decade {Ans: time period of 10 years}Era {Ans: period of time with common traits}