Why is function important to Aristotle's moral theory?

Sorry, but philosophically I am against doing homework for people, especially those who fail to complete their reading ignments or cannot perform a decent web search first. I'll give you a head start though: a href="http://www.google.com/search?q=Aristotle+%22function+argument%22&rls=com.microsoft:en-us:IE-SearchBox&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7ADRA_en" rel="nofollow"http://www.google.com/search?q=Aristotle…/a