Which of the following was a cause of the ecological disaster known as the dust dawn
a. a massive earthquake that loosened the topsoil
b. a flood in california
c. the plowing under the native grasses that kept topsoil in place
d. excessive rainfalls that year

Before tuberculosis was understood to be a communicable disease, and before the discovery of antibiotics to treat it, a major outbreak could kill or cripple a significant portion of a nation’s labor force. how would such an event affect the economy? illustrate the effect by dragging to shift either the aggregate demand curve or the long-run aggregate supply curve.

What was the midwest states often called because they were located in the center of the nation

What does it mean to say that "service sector" jobs are predominant in europe's mixed economies today? a. that jobs where people work in factories predominate b. that jobs where people do something for others predominate c. that jobs where people work the land predominate d. that jobs in government predominate