Here's a roundup of news trending across the nation and world today.

What to know now:

1. Republican debate: Marco Rubio  went after front-runner Donald Trump in Thursday's GOP debate, asking the New York billionaire to reveal his plans on health care, to explain why he hired foreigners to do jobs Americans could do and to account for the reason he flip-floped on deporting undocumented aliens. Rubio wasn't alone in attacking Trump -- Ted Cruz also went back and forth with Trump, questioning his conservative values. The  debate came five days before Super Tuesday – the day where nearly 700 Republican delegates are up for grabs in 13 state primaries and caucuses.

2. Three killed at factory: A  gunman shot and killed three people and wounded 14 at a lawn mower factory in Hesston, Kansas, Thursday. The  gunman, who used what witnesses said was an "assault-style" weapon during  the attacks, drove through the small town taking shots at people before  going to the factory where he had worked. The shooter was shot and killed by a law enforcement officer.

3. U.S. missile launch: The United States test-fired an intercontinental ballistic missile Thursday night, the second such test in a week. According to the Department of Defense, the launch of the unarmed Minuteman missile was meant to remind North Korea and Russia that the United States is well-prepared to defend itself with nuclear weapons should the need arise. The missile, launched from Vandenberg Air Force Base in California, landed one hour later some 4,200 miles away near Kwajalein in the Marshall Islands.

4. #WhichHillary: Hillary Clinton was the subject of the number one hashtag on Twitter for most of the day Thursday after a protester interrupted a speech and asked her to apologize for calling gang members "super predators." Clinton had used the term during a speech when she was first lady in the 1990s. The woman, Ashley Williams asked Clinton to "apologize to black people," and used the term #whichHillary on the bottom of a banner she was holding. #whichHillary soon topped Twitter's list of trending hashtags as people began to question Clinton's record. The attention came as Democrats are set to go to the polls to vote Saturday in the South Carolina primary.

5. Cosby drops suit, for now: Bill Cosby has dropped a defamation lawsuit against Beverly Johnson, the  supermodel who accused him of drugging her in the 1980s. According to the comedian's attorney, Cosby dropped the suit in order to focus on his defense in a criminal trial over allegations he drugged and sexually assaulted a former Temple University employee in 2004. Cosby plans to re-file the defamation suit against Johnson before the statute of limitations expires, his  attorney said. More than 50 women have come forward to accuse Cosby of drugging and/or sexually assaulting them.

And one more

The Academy Awards ceremony will air Sunday as controversy over the lack of diversity in Hollywood grows. Several black actors, actresses and directors have said they will not attend this year's ceremony. The Rev. Al Sharpton announced plans for a "nationwide TV tuneout" of the Oscar broadcast, along with a series of demonstrations and rallies to protest the lack of minorities in the industry and on the board of the Academy of Motion Picture Arts and Sciences – the body that chooses the nominees for the Oscars.

In case you missed it

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