Bret Baier this afternoon previewed tonight’s Fox News-Facebook Debate Event Night, which kicks off at 5p ET on Fox News Channel.

Baier, who will co-moderate the 9p ET prime-time debate, said that questions will span the gamut and will be a mix of the main issues that Americans care about.

Donald Trump, Jeb Bush, Scott Walker, Mike Huckabee, Ben Carson, Ted Cruz, Marco Rubio, Rand Paul, Chris Christie and John Kasich will participate in the 9p debate, which will be co-moderated by Baier, Chris Wallace and Megyn Kelly.

“I think there’ll be some interesting interactions between candidates on stage,” Baier predicted.

Candidates will have one minute to respond to questions, and they’ll be given an additional 30 seconds to respond to any follow-up questions. If a candidate attacks another contender by name, that person will be given 30 seconds to respond.

Baier also said that questions in the 9p debate could possibly change based on what happens at the 5p ET debate, moderated by Bill Hemmer and Martha MacCallum. The seven candidates participating in that debate are Rick Perry, Rick Santorum, Bobby Jindal, Carly Fiorina, Lindsey Graham, George Pataki and Jim Gilmore.

Baier said that any of those seven candidates could do or say something that causes them to surge in the polls.

“Any one of these people could eventually be president,” he said of the 17 candidates who will participate in one of tonight’s two debates.

Tune in to Fox News Channel starting at 5p ET for complete debate night coverage.

Rand Paul: Let's Have a Substantive Debate Rather Than a Superficial One

Rubio on Why He's Running: 'I Have a Debt to This Country I'll Never Repay'

Carson Ready for GOP Debate: 'It's Not Brain Surgery'