Studying is about not only learning some things from teachers but also about conducting the research by students on their own. That is why the research papers are a common assignments starting from high school.
The five paragraph paper is the universal structure for any possible writing. Such model can be used not only for essays but also for speech announcing or even for your answer during the class.
The key requirement for writing a synthesis paper is ability to grasp the information from different sources and to present it as an entirety. It develops strong analytical skills and an ability to digest and synthesize points.
An expository essay is not considered to be a difficult assignment. The main purpose of it is to explain or describe the subject of writing to the reader.