Answer:
Cities responded by paving streets, digging sewers, sanitizing water, constructing housing, and creating public transportation systems. Not only did urbanization cause cities to grow in population, but it also caused buildings to grow higher and larger.
Explanation:
Colonial era: british
WW1: American
WW2: British (America for the atom bomb... but thats just one weapon. and they massed produced everything else really)
after that: AMERICA!!
