The purchase of Michelin Tire Company by General Motors is an example of a vertical merger

If an indifference curve is a straight line it will not show which of the following?

A) any marginal rate of substitution B) diminishing marginal rate of substitution C) combinations of goods among which a consumer is indifferent D) None of the above answers is correct.

A central concept in macroeconomics is the idea of the natural rate of unemployment

Why does it make sense to define full employment to occur when the unemployment rate equals the natural rate of unemployment, instead of when the unemployment rate equals zero? Elaborate and explain carefully.