George Zimmerman’s defense attorney insisted during several testy exchanges with an important prosecution witness Thursday that Trayvon Martin injected race into a confrontation with the neighborhood watch volunteer and insinuated the young woman was not believable because of inconsistencies in her story.

However, 19-year-old Rachel Jeantel stood firm in her testimony about the night Zimmerman shot the unarmed black 17-year-old after a fight that Jeantel said she overheard while on the phone with Martin. Jeantel has said Martin told her he was being followed by a white man.

Zimmerman identifies as Hispanic. Race has permeated nationwide discussions of the case since the February 2012 shooting, which prompted nationwide protests and claims from critics that police took too long to arrest Zimmerman.

The neighborhood watch volunteer has pleaded not guilty and says he acted in self-defense.

Defense attorney Don West also zeroed in on slight differences among three different accounts of what happened before Martin’s killing, in an apparent effort to discredit her. Jeantel has described what she heard over the phone in a deposition; a letter to Martin’s mother; and an interview with the Martin family attorney. Among the differences highlighted by West:

— In some accounts, she said race was an issue but not in others.

— Jeantel testified Wednesday that her friend’s last words were “Get off! Get off!” before Martin’s phone went silent. But on Thursday, under cross-examination, she conceded that she hadn’t mentioned that in her account of what happened to Martin’s mother, Sybrina Fulton. She had left out some details to spare Fulton’s feelings, and also because neither Fulton nor the Martin family attorney asked her directly about them, Jeantel said.

— After Martin asks why he is being followed, Zimmerman responds, “What are you doing around here?” in one account by Jeantel. In another account, according to West, she says Zimmerman said, “What are you talking about?”

Zimmerman, 29, could get life in prison if convicted of second-degree murder. Zimmerman followed Martin in his truck and called a police dispatch number before he and the teen got into a fight.

Zimmerman has said he opened fire only after the teenager jumped him and began slamming his head against the concrete sidewalk. Zimmerman has denied the confrontation had anything to do with race, as Martin’s family and their supporters have claimed.

Jeantel testified Thursday that she thought race was an issue because Martin told her he was being followed by a white man.

But West responded, “It was racial because Trayvon put race in this?”

She answered no.

The exchanges got testier as the day progressed.

When asked by West if she had previously told investigators that she heard what sounded like somebody being hit at the end of her call with Martin, Jeantel said, “Trayvon got hit.”

“You don’t know that? Do you? You don’t know that Trayvon got hit,” West seized angrily. “You don’t know that Trayvon didn’t at that moment take his fists and drive them into George Zimmerman’s face.”

Later in the morning, West accused Jeantel of not calling police after Martin’s phone went dead because she thought it was a fight he had provoked.

“That’s why you weren’t worried. That’s why you didn’t do anything because Trayvon Martin started the fight, and you knew that,” West said.

“No sir!” Jeantel said. “I don’t know what you’re talking about.”

Thursday’s testimony began with a more subdued tone that it did a day earlier, when Jeantel frequently bristled at West’s questions and she at one point told him to move on to the next question: “You can go. You can go.”

West took note of her calmer demeanor in the morning. She answered many of West’s early questions by repeating “yes, sir,” almost in a whisper.

“You feeling OK today? You seem different than yesterday,” West said.

“I got some sleep,” she answered.