It all depends on what your subject area is and what your instructor requires.
Mostly, MLA is used for humanities courses: languages, literature, arts, etc.
Mostly APA is used for social science courses: psychology, sociology, etc.
Between APA and MLA which is the most important
Thank You
2 answers
http://www.google.com/search?q=mla+uses&rls=com.microsoft:en-us:IE-SearchBox&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7SUNA
http://www.google.com/search?q=apa+uses&rls=com.microsoft:en-us:IE-SearchBox&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7SUNA
http://www.google.com/search?q=apa+uses&rls=com.microsoft:en-us:IE-SearchBox&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7SUNA