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The second GOP presidential debate Wednesday on CNN produced a sea of soundbites along with several substantive moments.

Donald Trump opened strong but remained relatively tame most of the night, while Carly Fiorina and Jeb Bush both came out of the gate ready for battle and got in some strong zingers against the GOP frontrunner.

Here are the 5 most explosive moments.

Also Read: Hollywood Reacts to GOP Debate: Tom Hanks, Maria Shriver, Minnie Driver Weigh In

1. Trump Opens Strong, But Dials It Down Later

The GOP frontrunner opened by saying Senator Rand Paul is at “1 percent” in the polls and doesn’t belong on the stage, drawing noticeable groans from the crowd. He also gave a classic Trump resume opener. “I say not in a braggadocious way, I’ve made billions and billions of dollars dealing with people all over the world.”

The attack right off the bat gave viewers the impression that the outspoken former “Celebrity Apprentice” host had arrived for the second debate. But the GOP frontrunner stayed mostly calm, cool and collected for the remainder of the evening, mostly playing defense.

Also Read: 6 Things Scene and Heard at CNN's GOP Debate

Trump did get in a little sparring with Jeb Bush, Scott Walker and Carly Fiorina, slamming her tenure as head of Hewlett-Packard.

Her leadership at the firm “led to the destruction of the company,” he said. “She can’t run any of my companies — that I can tell you.” But even when many pundits have dismissed him as a bully, Trump has rebounded in the polls. This debate performance should be no different.

2. Bush Comes Out Swinging Against Trump

Jeb Bush was anything but low energy tonight, coming out more aggressive against Donald Trump.

“He supports [Nancy] Pelosi, he supports Clinton, he supports Schumer,” Bush said about the real estate mogul. Trump countered with his usual line about getting along with everyone as a businessman.

Bush also took aim at Trump for his endorsement of a negative tweet about the former Florida governor’s Mexican-American wife. Bush called on Trump to apologize to his spouse, who was sitting in the audience. Of course, the Donald did no such thing.

To wrap up the debate, Bush dropped in a high energy joke, even slapping hands with Trump.

Also Read: Donald Trump Deletes Tweet About Jeb Bush's Wife: You Like 'Mexican Illegals' Because of Your Wife

3. Fiorina on Fire

In a highly unscientific reporter’s eye test, Fiorina got the most applause, most frequently for her comments on Iran, the economy and of course, Donald Trump.

On Trump’s attacks on her looks, Fiorina was unwavering: “I think women all over this country heard very clearly what Mr. Trump said.” Trump countered that she has “a beautiful face” and is a beautiful person.

Many social media users agreed that Fiorina’s performance was strong. She’ll likely be among the favorites of the political pundits during Thursday’s post-debate analysis.

Also Read: Donald Trump Says Carly Fiorina Can't Be President Because 'Look at That Face!'

4. Chris Christie Goes Off on “Childish” Trump-Fiorina Feud

Annoyed by the time being sucked away during the ongoing Trump-Fiorina tit-for-tat, Chris Christie went off on the “childish” games.

“They can care less about your careers, they care about theirs,” Christie said about struggling American workers not needing to hear monologues on Trump or Fiorina’s track records as CEOs.

Also Read: Chris Christie Tells Jimmy Fallon He Will 'Go Nuclear' If Ignored in Next Debate (Video)

The New Jersey Governor got a round of applause from the debate, but his performance isn’t likely to lift him from low single-digit poll numbers.

5. Trump Blasts George W. Bush, Jeb Defends His Brother

In a continuation of the Trump/Bush battle, the GOP frontrunner slammed George W. Bush for giving America Barack Obama. According to Trump, the last few months of Bush’s administration were such a disaster that voters ran from Republicans and elected a Democrat as president.

Jeb defended his brother saying he kept the country safe, generating applause from the crowd. Social media — and liberal pundits — didn’t agree, immediately invoking 9/11.

The moment might help Bush in the post-debate pundit analysis, but is an attack ad waiting to happen from the likes of Hillary Clinton?

15 Most Cringe-Worthy Gaffes From Presidential Debates

1960: During the first televised presidential debate, Richard Nixon refused to wear stage makeup, revealing his sweaty forehead under the hot TV lights. This made the younger John F. Kennedy look much more confident.
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1976: Gerald Ford claimed that he didn't believe that Eastern Europe was under "Soviet domain," which proved to be an unpopular opinion, as the moderator repeated the question in bewilderment.
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1980: When the moderator tried to silence Ronald Reagan's microphone during a Republican primary debate, Reagan shouted: "I am paying for this microphone!" The line became a "political home run" for Reagan. It was also borrowed it from the 1948 film "State of the Union."
1980: In a general-election debate between incumbent president Jimmy Carter and Reagan, Carter said, “I had a discussion with my daughter Amy the other day before I came here to ask her what the most important issue was. She said she thought the control of nuclear weaponry.” Carter was mocked for taking policy advice from his 13-year-old daughter, helping Reagan to win the election.
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1988: Michael Dukakis may have lost the election when he said he would still oppose the death penalty even if the killer raped and murdered his wife, Kitty.
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1988: Vice presidential candidate Dan Quayle compared himself to Jack Kennedy and got hammered by Democratic rival Lloyd Bentsen: "Senator, I served with Jack Kennedy, I knew Jack Kennedy, Jack Kennedy was a friend of mine. Senator, you're no Jack Kennedy."
1992: George H.W. Bush checked his watch and tucked in his shirt during his debate with future president Bill Clinton, looking impatient when asked about the economy.
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2000: Al Gore sighed during a debate with George W. Bush, which was widely perceived as condescending. It was so bad, aides made him watch the "SNL" parody of the gaffe before the next debate.
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2008: Hillary Clinton attacked Barack Obama for allegedly lifting lines from the speeches of Massachusetts politician Duval Patrick. She had a good zinger... that didn't quite have the effect she was hoping for. "Lifting whole passages from someone else's speeches is not change you can believe in, it's change you can Xerox," Clinton said -- but the audience booed.
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2008: When a moderator asked Hillary Clinton if she had the personal appeal to overtake Barack Obama, the future president interjected that Clinton was "likable enough."
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2008: While illustrating a point about a Bush/Cheney energy bill that Obama had signed, Arizona Senator John McCain referred to the future president as "that one."
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2011: Texas Gov. Rick Perry shifted his reputation from budget-slasher to bungler when he blanked on the names of all three federal agencies he proposed to eliminate as president: "I can’t, the third one. I can’t. Sorry. Oops."
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2012: Former Massachusetts Gov. Mitt Romney claimed that Obama didn’t call Benghazi a terrorist attack. Obama confidently asked Candy Crowley to clear up the charge, which she does, pointing out Romney's mistake.
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2016: When asked during an interview in September what he would do about Aleppo, the epicenter of the Syrian refugee crisis, Libertarian presidential candidate Gary Johnson asked, "And what is Aleppo?" That line became a viral sensation, even earning some rather funny spoofs. Johnson then made things worse when later that month he couldn't name a single world leader -- dead or alive -- during a town hall with Chris Matthews. And just to be sure this second flub would get some traction, Johnson told Matthews he was having an "Aleppo moment." Talk about about a triple whammy.
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2016: Green Party presidential candidate JillS Stein was hoping to be the answer to Bernie Sanders after he dropped out of the primary race. But answer she gave during an AMA reddit sesh put a damper on her plans. Stein, a Harvard Medical School graduate, raised some eyebrows when she took a decidedly anti-vaxxer stance: "As a medical doctor, there was a time where I looked very closely at those issues, and not all those issues were completely resolved. There were concerns among physicians about what the vaccination schedule meant, the toxic substances like mercury which used to be rampant in vaccines. There were real questions that needed to be addressed." Stein later clarified that she was not, in fact, an opponent of vaccines.
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From Richard Nixon’s flop sweat to Rick Perry’s “Sorry oops,” candidates have often stumbled at the podium

1960: During the first televised presidential debate, Richard Nixon refused to wear stage makeup, revealing his sweaty forehead under the hot TV lights. This made the younger John F. Kennedy look much more confident.

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15 Most Cringe-Worthy Gaffes From Presidential Debates

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