Active participation in the classroom is not only accepted but also expected of the student in many courses. Some professors base part of the final grade on the student’s oral participation. Although there are formal lectures during which the student has a passive role (i.e., listening and taking notes), many courses are organized around classroom discussions, student questions, and informal lectures. A professor's teaching style is another factor that determines the degree and type of student participation. Some professors prefer to control discussion while others prefer to guide the class without controlling it. Many professors encourage students to question and challenge their ideas. Students who make statements that contradict the professor's point of view should be prepared to prove their positions.