The expansion of railroad directly led to economic growth in the us because

The expansion of railroads directly led to economic growth in the us because more people were able to commute to and from their workplace to their homes. Since some work opportunities before railroads were seen as too far away from home, once the railroads were created and trains were running on the tracks, the lengthy distances were shortened and people were able to look for jobs in places where they were more abundant, therefore boosting the economy.

From mexican american war , us gained new mexico.

Ithink the answer is d i hope it my friend message me if i’m wrong and i’ll change my answer and fix it for you