It was a war between America and Russia but they never attacked each other. America believed Capitalism was better but Russia believed Communism was the best. They just argued back and forth and raced to see who could get the most weapons in the end.
japan seized manchuria because japanese believed that japans empire should be equal to the size of the western powers empire
Blitzkrieg was so fast that the enemy didn't have time to prepare, whereas in WW1 where they fought in trenches, they would have to cross no-mans land and the enemy could see them coming
D. sending a text messages on your cell phone
hope this helps