Americans can i look forward to a future where there is no more we just had our challenges have all been met

porter is writing economic history because he is focusing on the cost of developing vaccines.

no options provided, here,but the answer to this question is often: a historian cites a japanese newspaper article published a year after the end of world war ii in order to draw conclusions about the effect of the war on the japanese economy.

clearly from the answer, the historian alludes to historical sources,and records to aid in analyzing and drawing conclusion on the effect of the war on the economy of japan.