It may be the largest—or only—factor in the student's course grade; in other cases, it may carry the same weight as a midterm exam, or the student may be exempted. Not all finals need be cumulative, however, as some simply cover the material presented since the last exam. For example, a microbiology course might only cover fungi and parasites on the final exam if this were the policy of the professor, and all other subjects presented in the course would then not be tested on the final exam.