Aggression key to Cain's success

The final Report Card for 2012 hones in on UFC 155, a deep lineup that produced several memorable outcomes and -- no small feat -- 17 grades. The event, of course, delivered one of the best UFC heavyweight title fights in years between Junior dos Santos and Cain Velasquez.

The title-changing fight was a showstopper. The Las Vegas card also hashed out a few things at 185 and 155 pounds, offering more intriguing possibilities as we head into the new year.