An expository essay is a formal academical paper in which the main purpose of the author is to explain, clarify or illustrate a topic or situation, instead of persuading as most of the essays. As other essays, an expository essay is composed of an introductory paragraph followed by a set of development paragraph and a conclusion paragraph. Additionally, as this is an academical paper and the author is writing about some topic he might know or be interested without being an expert it is necessary to use other sources, this means the explanation and position from the author are supported by other authors and materials that provide credibility to the author's words. These external works and authors should be referenced during the text and at the end of it (referenced source material), in this way, the reader knows from whom did the author take the information. Considering this, any well-written expository essay needs to include referenced material, because these materials provide credibility to the paper. Also, other options as sensory details and personal information should not be included as these are too informal and as it aims at explaining not at persuading persuasion is not relevant.
She is relying on the primary source. This is because, the writer is first hand information about the experience of the author. What made it a primary source is also coupled with the fact that, the writer is the one that experience it and the one that is wrote the book based on his experience.
