A paragraph is one or more sentences focusing on a single subtopic or idea which serves as a visual signal, helping readers to see divisions within the larger whole. Without paragraphs, texts would be harder to read and decipher. However, in business and technical writing, most paragraphs have 2 to 5 sentences and rarely exceed 150 words. A paragraph provides subtopic definition and visual relief to make reading easier.
Visual appearance is affected by the format of the document.
In fact, a paragraph with a single sentence is very emphatic because it stands out compared to other longer paragraphs which may surround it. Varying the length of paragraphs helps stimulate reader interest. Obviously, the length of a paragraph depends on its content. Then, explanatory paragraphs which follow can be longer, providing necessary examples and details. For clarity, whatever organizational structure is used should be very evident to the reader.