SANFORD, Florida (AP) — 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 entered a second day of deliberations Saturday.Whose screams are on the 911 calls?Who was on top during the scuffle?How did the position of Martin’s arm change?Did Zimmerman act in self-defense?Did Zimmerman act with ill-will, hatred, spite or evil intent?

During almost three weeks of testimony, they listened to 56 witnesses — 38 for the prosecution and 18 for the defence. A number of items have been the source of conflicting testimony, and jurors will have to sort out those contradictions in the deliberation room.

Zimmerman is pleading not guilty to second-degree murder. He says he fatally shot Martin in a scuffle at the townhome complex where Zimmerman was a neighbourhood watch volunteer and where Martin was visiting his father’s fiancee.

Martin was black and Zimmerman identifies himself as Hispanic. 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 have to sort out.

Convincing jurors about whose voice is screaming for help on 911 calls that captured audio of the fight was the primary goal of prosecutors and defence 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 neighbours. Zimmerman’s mother, uncle, father and five friends told jurors it was the neighbourhood watch volunteer’s voice. One of Zimmerman’s neighbours, 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 neighbour 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 manoeuvre known as “ground and pound.” Neighbours Selma Mora and Surdyka say the person on top got up after the shooting. Zimmerman’s attorneys say 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 neighbour shows Martin’s arms under his body. Defence 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. In their jury instructions, jurors were told self-defense is justified in using deadly force if Zimmerman reasonably believed that such force was necessary to prevent imminent death or great bodily harm to himself.

To get a second-degree murder conviction, prosecutors must show that Zimmerman acted with ill will, hatred, spite or evil intent. Prosecutors argued that profanities Zimmerman uttered under his breath while he watched Martin walk through his neighbourhood were evidence of ill will and hatred. But when asked by prosecutors and defence attorneys, no witness said Zimmerman acted with these traits. The judge presiding over the case also is letting jurors consider the lesser charge of manslaughter. To get a manslaughter conviction, prosecutors must show only that Zimmerman killed without lawful justification.