Final answer:
Each subtopic or supporting idea in an outline is not always represented by a number followed by a period, but by various symbols depending on its position in the hierarchy of the outline. Outlines are essential for linking ideas and ensuring paragraph coherence and unity under a central thesis. The statement is false.
Step-by-step explanation:
False. In a traditional outline structure, each subtopic or supporting idea is typically represented by a capital letter followed by a period, or a lowercase letter, number, or Roman numeral, depending on the level of detail and hierarchy within the outline. Therefore, while numbers may be used, they do not always follow the format of a number followed by a period. For example, a main topic might be represented as 'I.', a subtopic as 'A.', and a detail under the subtopic as '1.'.
The purpose of an outline is to organize the writer's thoughts and ideas in a logical manner, detailing how one idea connects with another, how one paragraph connects with another, how one idea supports or refutes another, and offering a preview of what is to come in the essay. Outlines are particularly useful for ensuring that each paragraph is unified under a single, clear topic, with background and supporting details that provide a sense of completeness.
Moreover, in well-written essays, paragraphs align with the thesis statement, which is the central argument of the essay. Topic sentences are used to lead the paragraphs, and transitions are employed to ensure fluid movement between ideas. Visuals and evidence of qualitative and quantitative data also play a role in clarifying abstract ideas or providing comprehensive support to the essay's argument.