Question: What is the ranking system used in combat sports, including boxing and mixed martial arts, of who the better fighters are relative to their weight, by which measure the Polish mixed martial artist Joanna Jędrzejczyk is rated the number 1 female MMA fighter in the world?
Sentence (from "Guy Mezger"): Guy Mezger (born January 1, 1968) is an American martial artist, who competed in professional combat sports including full contact karate, kickboxing, and boxing, but is most recognized as a mixed martial arts (MMA) fighter.
Relevant evidence: No