Over the last fifty years both real GDP and prices have trended upward in most countries. Continuing real GDP growth and inflation can be explained by

1) the stages a new product goes through from beginning to end, i.e., the stages that a product passes through from introduction through growth, maturity, and decline. 2) the time from initial research and development to the time at which sales and support of the product to customers are withdrawn. 3) the period of time during which a product can be produced and marketed profitably.

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answer; microeconomics;

the correct choice is a