Democratic debate: Protesters interrupt Joe Biden during his closing segment

Warren says that "we cannot keep asking our military to keep solving problems that cannot be solved militarily."

She is saying that an international effort must be taken to fight terrorism, and that bombs are not the only answer.

Warren says she was with John McCain in Afghanistan two years ago, and says she talked to people on the ground there.

Sanders says "I never believed" what the Bush administration said about weapons of mass destruction in Iraq, after Biden claimed he was against the Iraq war after he found out there was no yellow cake uranium.

Sanders says that is unfair to compare his form of Democratic socialism to what is happening in Venezuela.

He compares his policy ideas to what you see in Canada or in Scandinavia, with universal healthcare coverage.

Castro calls for 21st century Marshall Plan for Honduras, Guatemala, and Nicaragua.

Booker, a vegan, says that he does not think that solving climate change's problems means everyone needs to follow the same diet as him. He says that factory farming, however, is detrimental.

Warren says that climate change "is the threat to every living thing on the planet". 

She says that she wants to use regulations to cut carbon emissions.

Harris says she looks at the issue of climate change "through the lens" of her baby nieces.

She also says that Republicans lack "courage" in addressing the climate crisis.

"I am pro good school," Yang says.

He notes that his child just started public school last week, and calls for paying teachers more.

He says that "we need to lighten up our emphasis on standardized tests".