Questions Jurors Must Consider in Zimmerman Trial The six female jurors who will determine whether George Zimmerman committed second-degree murder when he fatally shot 17-year-old Trayvon Martin last year could begin deliberating as early as Friday. During almost three weeks of testimony, they have listened to 56 witnesses - 38 for the prosecution and 18 for the defense. A number of items have been the source of conflicting testimony, and jurors will have to sort out those contradictions once they get in the deliberation room. He claims he fatally shot Martin in a scuffle at the townhome complex where Zimmerman was a neighborhood watch volunteer and where Martin was visiting his father's fiancee. Some civil rights activists argued that the delay in charging Zimmerman was influenced by Martin's race, and protests were held around the nation in the 44 days before Zimmerman was arrested. Here are five questions jurors will have to sort out. Convincing jurors about whose voice is screaming for help on 911 calls that captured audio of the fight has become the primary goal of prosecutors and defense attorneys. Martin's mother, father and brother testified it's the Miami teen screaming for help on recordings of the 911 calls made by Zimmerman's neighbors. Zimmerman's mother, uncle, father and five friends told jurors it was the neighborhood watch volunteer's voice. One of Zimmerman's neighbors, Jayne Surdyka, says the screams were those of a boy. Zimmerman was wearing a red jacket and Martin had on a dark hoodie. Zimmerman's former neighbor Jonathan Good, perhaps the witness with the best view of what happened, says he saw a person in dark clothing straddling someone in red or white clothing and making downward movements with his fists in a mixed-martial arts maneuver known as "ground and pound." Neighbors Selma Mora and Surdyka say the person on top got up after the shooting. Zimmerman's attorneys claim Zimmerman had been on the bottom but got on top of Martin after he fired his gun. Zimmerman told investigators that Martin was on top of him, pounding his head into the pavement. After he fired his gun, he says, he got on top of Martin and spread his arms. However, a photo taken moments later by Zimmerman's neighbor shows Martin's arms under his body. Defense expert Vincent DiMaio testified Martin could have moved his arms in the 10 to 15 seconds he would have been conscious after being shot in the heart. Zimmerman has argued all along he acted in self-defense, although he passed up chance for a self-defense "stand your ground" hearing in which a judge could have thrown out the case without it going to a jury if the judge was convinced there was enough evidence to support it. Zimmerman's community college instructor, Alexis Francisco Carter, told jurors that a person can claim self-defense if they have a reasonable fear of death or great bodily harm. Jurors will get further instructions on self-defense from the judge. In order to get a second-degree murder conviction, prosecutors must show that Zimmerman acted with ill will, hatred, spite or evil intent. Prosecutors have argued that profanities Zimmerman uttered under his breath while he watched Martin walk through his neighborhood were evidence of ill will and hatred. But when asked by prosecutors and defense attorneys, no witness said Zimmerman acted with these traits. Follow Mike Schneider on Twitter at http://twitter.com/MikeSchneiderAP .