Why is it important to line up the decimal points?

When we add decimals, we have to line up the decimal point and decimal places. This is because we have to add the tens to the tens, the ones to the ones, the tenths to the tenths, the hundredths to the hundredths, and so on.

industry had made the u.s. the richest nation in the world at this time. the second industrial revolution caused growth in industry and transportation, which allowed increased trade between nations.

the answer is:

c. economic output