How did the physical of the united states contribute to its economic growth?

Distance that the transcontinental railroad covered from omaha to san francisco.

If we represent the solar system on a scale that allows us to walk from the sun to pluto in a few minutes, then a) the planets are microscopic and the stars are millions of miles away. b) the planets are the size of basketballs and the nearest stars are a few miles away. c) the planets are marble size or smaller and the nearest stars are thousands of miles away.

About 140,000 japanese died in this japanese city when americans dropped an atomic bob at the end of world war ii