Trump, Biden clash in final debate on COVID-19 response, health care, race

To open the section on race in America, Welker described "the talk" to the candidates -- when parents of color, regardless of class or income, prepare their children for the chance that they could be targeted by police for no reason other than the color of their skin -- giving the first question to Biden. 

"I would like you to speak directly to these families," Welker said. "Do you understand why these parents fear for the children?"

"Yes, I do," said Biden. "The fact of the matter is there is institutional racism in America. We have always said, we've never lived up to it, that we hold these truths to be self-evident, all men and women are created equal. Guess what? We have never, ever lived up to it."

"We have to provide better economic opportunity, better education, better health care, better access to schooling, better access to borrow money to start businesses," Biden continued. "And I've laid out a clear plan as to how to do those things just to give people a shot. It's about accumulating the ability to have wealth as well as it is to be free from violence."

When the same question was posed to Trump, the president raised Biden's controversial 1994 crime bill and again said no one has done more for the Black community than Trump -- other than President Abraham Lincoln. 

"Yes, I do," Trump said, before launching an attack on Biden. "And again, he's been in government 47 years. He never did a thing, except in 1994, when he did such harm to the Black community."

"Nobody has done more for the Black community than Donald Trump. And if you look, with the exception of Abraham Lincoln, possible exception, but the exception of Abraham Lincoln, nobody has done what I've done," he added. 

Trump went on to rail against Biden for not making the changes he's pushing when he was in office and said he ran for office as a direct response to Obama and Biden. 

"Joe, I ran because of you. I ran because of Barack Obama. Because you did a poor job. If I thought you did a good job, I would have never run," Trump said. "I ran because of you."

Fielding Trump's misleading claims that he would ban fracking, Biden made what Trump called a "big statement" when he said, "By the way, I'd have a transition from the oil industry, yes."

"Why would you do that?" Welker followed up.

"Because the oil industry pollutes significantly," Biden said. 

"Oh, I see," Trump interjected. "That's a big statement."

"If you let me finish a statement -- because it has to be replaced by renewable energy overtime. And I'd stop giving to the oil industry, I'd stop giving them federal subsidies," Biden continued.

"He's going to destroy the oil industry," Trump said. "Will you remember that, Texas?  Will you remember that, Pennsylvania, Oklahoma?"

Biden responded by saying Trump "takes everything out of context." 

Trump said his administration is "trying very hard" to locate the 545 children whose parents can't be located after being separated from their parents. However, the president also said that some of the children were brought to the U.S. by "coyotes" and "cartels."

He then pivoted to say that the Obama administration built the detention centers where many migrants are held.

"They had a picture in a certain newspaper, there was a picture of these horrible cages. They said look at these cages. President Trump built them," Trump said. "Then it was determined they were built in 2014. That was him. They built cages." 

In a fiery response, Biden emphasized that the children came to the U.S. with their parents. 

"Coyotes didn't bring them over, Biden said. "Their parents were with them. They got separated from their parents, and it makes us a laughingstock and violates every notion of who we are as a nation. 

Welker asked about the Obama administration's failure to deliver on immigration reform. Biden said that it took too long to get the policy correct.

"It took too long to get it right. Took too long to get it right," he said. "I will be president of the United States, not vice president of the United States. And the fact is, I've made it very clear, within 100 days, I going to send to the United States Congress a pathway to citizenship for over 11 million undocumented people and all of those so-called dreamers, those DACA kids, they are going to be immediately certified again to be able to stay in this country and put on a path to citizenship."

Trump responded that Biden "had eight years to do what he said he was going to do."

Biden and Trump then went back and forth over the catch-and-release policy.

TRUMP'S CLAIM: "Nobody knew where it was coming from, what it was. We've learned a lot. But Anthony said don't wear masks. Now he wants to wear masks."

FACT CHECK: Dr. Anthony Fauci, one of the top infectious disease experts in the country, and other public health experts initially told Americans not to wear surgical or N95 masks in the early days of what has become the COVID-19 pandemic.

At the beginning of the pandemic, the Centers for Disease Control and Prevention and the World Health Organization, as well as Fauci and other top experts, initially discouraged wearing masks because of concerns that masks and other personal protective equipment were in short supply for health care workers who needed them. Public health officials were also concerned wearing masks could have unintended consequences if people touched their face more often to adjust them or fail to keep social distancing. 

"There was this feeling that there would be a shortage just for those who really need them very early on," Fauci said in a recent interview. "That was the big deal. We didn't have enough PPE including masks. Then it became clear that cloth masks worked reasonably well. And therefore there was no more shortage. Then the different analyses, meta analyses and others came in that in fact, it does work."

In early April, the CDC changed its recommendation about face coverings for the general public, based on evidence that a significant number of people who were asymptomatic or not yet feeling sick were transmitting the virus.

Duke University researchers have also concluded that "if 95 percent of people wear cloth masks when within 6 feet of other people in public, it will reduce COVID-19 transmission by at least 30 percent."

Trump also said he thought Fauci was a Democrat, but Fauci is not registered as a member of any political party, according to D.C. voting records.

-ABC News' Stephanie Ebbs and Arielle Mitropoulos