The candidates are dealing with health care, immigration, race issues, taxes and the economy.
In arguing for a candidate from a new generation to be the Democratic nominee, California Rep. Eric Swalwell quoted then-Sen. Joe Biden speaking in 1987 at the California Democratic Convention.
"I was six-year-old when a presidential candidate came to the California Democratic Convention and said, 'It's time to pass the torch to a new generation of Americans.' That candidate was then-senator Joe Biden, and Joe Biden was right when he said it was time to pass the torch to a new generation of Americans 32 years ago If we are going to solve the problem of climate chaos, pass the torch. "If we are going to solve school violence, pass the torch."
Undocumented immigrant contributions to Social Security
Former Vice President Joe Biden said, "Undocumented immigrants actually contribute to the wellbeing of the country, also for example, increase the lifespan of social security, because they have a job, they are paying a social security tax, that's what they're doing.
Facts First: This is true.
Andrew Yang claimed that Amazon pays "literally zero in taxes." "Oh, so, it's difficult to do if you have companies like Amazon, trillion-dollar tech companies paying literally zero in taxes while they're closing 30% of our stores."
Facts First: When it comes to taxes, the picture is more complicated than Yang claims. Amazon pays state taxes and has also paid federal taxes in the past.
"From 2012 through 2018, Amazon reported $ 25.4 billion in pretax US income and current federal tax provisions totaling $ 1.9 billion," the Journal reported. "Looking back further, since 2002, Amazon has earned $ 27.7 billion in global pretax profits and paid $ 3.6 billion in global cash income taxes and a 13% tax rate."
Analysts say Amazon was able to whittle down its tax liability by tax credits and deductions.
Bernie Sanders claimed "83% of your tax benefits go to the 1%.
Facts First: This is incorrect. For the 2018 tax year, the top 1% was estimated to have received 20.5% of the benefits from the tax cuts, according to the non-partisan Tax Policy Center.
Some estimates say that if certain tax cuts were not reapproved by the Congress after they sunset in 2027, 83% of the benefits would go to the top 1%.
Trump's tax bill
California Sen. Kamala Harris claimed that the tax bill signed by President Donald Trump will benefit major corporations and will contribute at least $ 1 trillion to US debt.
Facts First: This is true. The Congressional Budget Office estimated that the 2017 tax act would add some $ 1.9 trillion to the federal deficit over the next decade.
-Maegan Vazquez and Holmes Lybrand
America's wealth gap
Sen. Bernie Sanders blasted the rich for taking advantage of America, saying that three people own more wealth than the bottom half of the nation.
Facts First: I It's true that the three richest Americans have more wealth than the bottom half of the nation, according to a 2017 study by the left-leaning Institute for Policy Studies.
The Institute used data from the 2017 Forbes 400 list and the Federal Reserve's 2016 Survey of Consumer Finance.    
US homeless population
In calling for change, Bernie Sanders said "500,000 people are sleeping out on the streets today."
Facts First: Sanders is basically correct here. While the number of people experiencing homelessness fluctuates in the United States, the most recent government tally lines up with Sanders' claim.
This story is broken and will be updated