Are jobs the key to economic progress and the achievement of high income levels? a. no, it is not just employment, but employment that expands production of goods and services that others value highly relative to cost. b. yes, when full employment is present, income levels will be at their maximum. c. yes, as long as people are working, real income levels will be high. d. uncertain, additional employment will increase real income only when the general level of prices is unchanged.