What is a group of sentences and paragraphs that are tied together by one unifying idea has been developed sufficiently?

An essay is a group of sentences and paragraphs that are tied together by one unifying idea has been developed sufficiently. It is usually written in a formal style and follows a specific structure. An essay typically begins with an introduction, which presents the main idea of the essay. The body of the essay then develops the main idea by providing evidence and analysis. The essay concludes with a conclusion, which summarizes the main points of the essay and leaves the reader with a final thought.