The United States allowed immigration to help the victims avoid the Holocaust although not in the larger numbers that could have been more helpful. The United States entered the war in 1941 and also attacked Germany in retaliation. The Holocaust continued because the Nazis had a very well organized system of apprehension of people that were put in the camps.
The answer is D) Nationalism.
First by hiding them from others, and if others were to try and confiscate their food they would fight them off with what weapons they had like spears, fire, and bow and arrows
To preserve the balance between slave states and free states
There are about 7,643,402,521
people in the world. However there are people being born and dying every few seconds. So as of right now there is 7.74 billion people! :)
I'm glad I could assist you! Have a great day!