Final answer:
The style of writing that utilizes examples to clarify a topic's fundamental qualities and substantiate the thesis is known as illustration, playing a vital role in an expository essay to effectively communicate the writer's message.
Step-by-step explanation:
The style of writing that uses examples to reveal a topic's essential characteristics and reinforce the thesis is known as illustration. This type of writing is crucial in an expository essay, where the goal is to explain or clarify a topic. Illustration involves using specific examples to demonstrate the truth of the topic sentence's point, thereby providing a reason for its claim.
It is part of the larger process of integrating evidence to support a thesis, which may include an illustration of the topic sentence's point, an explanation of the point, or evidence that demonstrates the point's validity. Effective illustration not only clarifies the thesis but also helps the audience understand the subject matter by using concrete examples.
In writing and speaking, these examples also contribute to the overall rhetorical effectiveness by appealing to readers' intelligence and sympathies, thereby conveying the writer's message clearly and persuasively.