Why was the american federation of labor (afl) called the "bread and butter" union?

What event brought the us into wwii? what conflicts happened after the us entered the war? i know the first part of this question, i need with the second part.

Apurging of emotions, specially pity and fear

Which of the following led to a continuation of the treatment in the excerpt above? a)the brutality of the trans-atlantic african slave trade. b)spanish repression after violent native uprisings in new spain during the 16th century. c)european competition to quickly establish colonial holdings in the new world. d)the reliance of the spanish on native americans to provide labor under the encomienda system.