Because joe biden like to eat pizza and get fat
There were many reasons. For starters, it involved getting rid of a large number of Native Americans, and while some supported this, others opposed it as they were peaceful. Another thing was that this meant the introduction of new states and it deepened the division based on whether the states should be slave states or non-slave states. Also they involved war with Mexico and some wanted this and some didn't.
Answer:
The answer is b. A strategic location for trade
A country would want to get a larger military to overpower or to stand ground against other counties. "Problems" that this could cause to a nation is to be over militarized and not care about its citizens, problems to surrounding nations is that they would feel threatened by a larger military.