Final answer:
The nativism of xenophobia during World War I was characterized by a fear of foreign influence and a preference for White Americans with older family trees. This fear was driven by events such as anarchist assassinations and the Bolshevik Revolution, which heightened concerns about a perceived foreign or communist threat.
Step-by-step explanation:
The nativism of xenophobia during the World War I period is characterized by a fear of foreign influence. Nativists valued White Americans with older family trees over more recent immigrants and rejected outside influences in favor of their own local customs. This fear was fueled by events such as the anarchist assassinations and the Bolshevik Revolution, creating a sense of perceived foreign or communist threat.