Answer:
I do not have the novel on hand so you may need to find some examples of your own. However, Harper Lee uses Scout, a child, to narrate because it affects the atmosphere and perspective of the novel. Because the novel is through Scout's perspective, we never hear an opinion on race unless it is in quotation marks. We read the story from her young and not fully developed mind whereas if we read it through an adult mind, we might have heard opinions or had more answers.