One effect of the novel’s use of a first-person narrator is that

One effect of the novel’s use of a first-person narrator is that it gives an insight about narrator's thoughts and feelings.

Explanation:

When a novel is written with the point of view of a first person, the reader comprehends the story from the narrator's perspective.

So it becomes easier for the reader to understand the feelings of what the writer had tried to convey to his readers.

it not only provides the outer perspective but also gives an insight on narrator's thoughts and feelings.

because of all the immigration, america became one big melting pot. the diversity of cultures from all over the world made america somewhat divided as well. people that immigrated stayed with their kind, and their traditions, while native born americans stayed with their kind and their traditions. normally, people born in american scorned the immigrants as well. the new religions also divided america. in summary, it took away from the american culture and identified america as the "melting pot."