What element is commonly used to enhance understanding in an expository piece?

Using statistics and factual information is a fundamental element in enhancing understanding in an expository piece. Expository writing aims to inform or explain a topic to the reader clearly and logically. By incorporating data, statistics, and factual evidence, the writer provides a solid basis for the claims made, allowing the reader to grasp the content more effectively. This type of empirical evidence can lend credibility to the writing and helps to clarify complex ideas, making them more understandable.

While imagery, biography, and dialogue may be useful in other types of writing, such as narrative or descriptive pieces, they do not serve as the primary means of conveying factual information in expository writing. Imagery enhances the reader's experience and evokes emotions, but it doesn't necessarily clarify or explain concepts as effectively as statistics can. Biographies may provide context or background but are not essential in an expository format focused on factual clarity. Dialogue can contribute to character development and engagement in storytelling but is less relevant for straightforward informational writing. Thus, using statistics and factual information aligns with the goal of expository writing, which is to elucidate and inform.