Answer:
Use of copper and a lot of the nations money left us in the great depression.
Germany.....?
I will tell you a little bit about what happened. At the end of WWI Germany was made to take blame for WWI. Pay reparations. Have their military cut down and weapons were non existent. This is why WWII happened the Allies disabled them so much they got angry and so the rise of Hitler.
The Mexican Cession happened in 1848. In this treaty, Mexico handed over Texas to the US. Hope this helps.