What is part of an effective introduction? a piece of evidence to support the claim
an interesting quote or fact about the topic
a reason the reader should agree with the writer
an explanation of how the reader can help

an interesting quote or fact about the topic

Explanation:

world war i had a devastating effect on german-americans and their cultural heritage. up until that point   german-americans, as a group, had been spared much of the discrimination, abuse, rejection, collective mistrust experienced by so many different racial and ethnic groups in the history of the united states. indeed, over the years, they had been viewed as a well integrated and esteemed part of american society. all of this change with the outbreak of war.  

answer; provide for the common defense: