The Japanese truly believed that America was going to attack them, so out of paranoia, they decided to attack first. Pearl Harbor had the airrafts and ships that would be used in war, so it was a perfect target for them because it would give them more time to prepare themselves against America. Unfortunetly for Japan, America was able to mass produce its aircrafts and ships and managed to quickly replace all the damaged vehicles.
I hope this helps.
That would be productivity.
It was the year 1798 that Thomas Malthus predicted that the humanity would be met with mass starvation. His prediction was based on an assumption that human population would far exceed the means of producing food and that we just would not be able to produce enough food for everyone. But the technological advancement and the advanced farming techniques allowed us to increase productivity and thus avert this prediction.
They fought with the americans becaues the revolutionary war was to end slavery so they blacks helped them fight the war so they could be free and no longer slaves.