Answer:
Because the Topic sentences help keep your writing focused and guide the reader through your argument. In an essay or paper, each paragraph should focus on a single idea. By stating the main idea in the topic sentence, you clarify what the paragraph is about for both yourself and your reader.
A topic sentence must highlight the main idea of a paragraph, letting the reader know what the paragraph will be about. The topic sentence must present an idea that will unify the rest of the paragraph while relating it back to the main thesis of the paper. The topic sentence is usually the first sentence of the paragraph because it gives an overview of the sentences to follow. The supporting sentences after the topic sentence help to develop the main idea. These sentences give specific details related to the topic sentence.
Explanation:
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