Final answer:
The sentence with parallel structure is 'The author argues for and then against the rezoning proposal.' Parallelism improves readability and clarity by presenting similar ideas in a consistent way, which is important for effective writing and speeches.
Step-by-step explanation:
The sentence that exhibits parallel structure is "The author argues for and then against the rezoning proposal." In this sentence, parallelism is achieved through the symmetry of the actions 'argues for' and 'argues against,' which are both phrased similarly. Parallelism is important in writing because it creates a rhythm and balance in the sentence, making it smoother and easier to read. It enhances the clarity and persuasiveness of writing by showing the relationship between ideas more clearly and emphasizing points effectively.
An important aspect of strong writing is its organizational structure. For example, President John F. Kennedy used parallelism in his inaugural address to effectively organize his support for the idea of collaborative efforts towards liberty, demonstrating the strong impact that parallelism can have in speeches and writing.