Figure 43-3
Use the figure to answer the corresponding question(s) . 
-In Figure 43-3 the structure labeled 4 is:
Definitions:
Economic Fluctuations
The ups and downs in economic activity, characterized by periods of expansion and contraction in GDP and other economic indicators.
Production Possibilities Curve
A graphical representation that shows the maximum quantity of one good that can be produced for every possible level of production of another good, assuming a fixed amount of resources.
Opportunity Costs
The cost of forgoing the next best alternative when making a decision or choosing between options.
Production Possibilities Frontier (PPF)
A curve depicting the maximum output possibilities for two goods, given a set of inputs and technology, illustrating the trade-offs in production choices.
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Q75: Refer to Figure 40-1.Which of the following
Q85: Refer to Figure 43-5.Which of the following