Courses in American universities are usually on a time constraint. Some courses are only a few weeks long, one semester long, last an academic year (two semesters), and even three semesters long. A course is usually specific to the students’ major and is instructed by a professor. For example, if a person is taking an organic chemistry course, then the professor would teach the students organic chemistry and how it applies to their life and or major. Courses can also be referred to as “electives”. An elective is usually not a required course, but there are a certain number of non-specific electives that are required for certain majors.