(CNN) Former Vice President Joe Biden expanded his winning coalition on Tuesday night, delivering another commanding win in the South with black voters and moderates while also winning over groups that went for Vermont Sen. Bernie Sanders in 2016, according to preliminary exit polls.

White college-educated voters left Sanders and threw their support behind Biden. Sanders also lost support with independent voters, another key demographic, who backed the democratic socialist senator by far smaller margins than they did four years ago.

The results followed a pattern established on Super Tuesday , as Biden continues to consolidate a Democratic electorate that is supremely focused on one goal: Defeating President Donald Trump in November.

Here's what we saw in exit polls Tuesday night:

Biden's win is Sanders' loss in Michigan and Missouri

In both Michigan and Missouri, Biden drew support from groups that Sanders won by significant margins in 2016, especially white voters.

In Michigan, preliminary exit polls showed Biden and Sanders about even among college-educated white men, despite Sanders winning that group by nearly a 2-to-1 margin four years ago.

Independent voters favored Sanders by 43 percentage points over Hillary Clinton in 2016, but he led Biden only by single digits in 2020.

Missouri exit polls showed Biden significantly leading Sanders among men without a college degree, a group that Sanders won in 2016 by 60%, topping Clinton by 21 percentage points. Sanders also lost support among independent voters in Missouri: around half voted for him in 2020, a drop from about 67% in 2016.

Mississippi continued Biden's Southern sweep

Black voters in Mississippi delivered yet another commanding win for Biden in the South, as he aimed to build his delegate lead and capitalize on the momentum that started with his February 29 win in South Carolina.

Around two-thirds of the Democratic primary electorate in Mississippi was black, and those voters supported Biden by an almost 8-to-1 margin, with almost 9 in 10 saying they voted for Biden vs. only a little over 1 in 10 for Sanders. Seven in 10 black voters in Missouri also cast their ballots for Biden Tuesday.

Democratic voters trust Biden over Sanders to handle a crisis

The exit polls showed Democratic voters trust Biden more than Sanders to handle a major crisis.

In Missouri, results show a broad 6 in 10 Democratic primary voters trusted Biden most to handle a major crisis, while about a quarter named Sanders.

In Michigan, where the exit poll reflected only those who voted on Election Day, roughly half of Democratic primary voters said they trust Biden most among the Democratic candidates to handle a major crisis. About a third say they trust Sanders most to handle a crisis.

The numbers are similar in Washington state, where about half of Democratic primary voters said they trust Biden to handle a crisis. About a quarter chose Sanders and roughly 1 in 5 chose Massachusetts Sen. Elizabeth Warren, who dropped out of the race on Thursday. Voters cast their ballots by mail in Washington, and many ballots were mailed before the field of candidates winnowed over the past week.

The night's biggest prize: Michigan

Around 4 in 10 Michigan Democratic voters chose health care as their top issue, according to early exit polls. About a quarter chose income inequality, 1 in 5 named climate change and 1 in 10 chose race relations.

Almost 6 in 10 voters in Michigan whose top priority is health care supported Biden for the nomination, while around 4 in 10 went for Sanders. Sanders narrowly beat Biden among voters who prioritized income inequality.

Almost 6 in 10 support replacing private health insurance with a single government plan for all. And around half say the nation's economy needs a complete overhaul, while over 2 in 5 want minor changes and less than 1 in 10 think it works well as is.

Supporters of a private insurance plan went for Sanders, around 6 in 10, while around three quarters of voters who opposed it voted for Biden.

The coronavirus factor on the 2020 race

In Washington, where there has been a concentration of coronavirus cases, more than 8 in 10 Democratic primary voters said they were at least somewhat concerned about the effects of the outbreak, including nearly 4 in 10 who said they were "very concerned."

The Biden and Sanders campaigns both canceled rallies on Tuesday night.

Older voters there were more apt to be concerned than younger ones, with around half of those age 65 and older saying they are "very concerned" about it, compared with just 1 in 7 of those under age 45.

Looking ahead to November: How Democrats will take on Trump

Almost 9 in 10 Democratic voters in Washington said they would vote for the Democrat in November regardless of who the nominee is, according to early exit polls. Around 8 in 10 in Michigan said the same -- including 9 in 10 Biden supporters and 8 in 10 Sanders supporters. About 1 in 5 Sanders voters in Michigan would not commit to voting Democratic in November regardless of who the nominee is.

About 6 in 10 Democratic primary voters in Michigan and even more in Washington, 8 in 10, are angry at the Trump administration. Only single digits said they were enthusiastic or satisfied regarding the current administration.

Preliminary exit polls in Michigan show around 3 in 5 Democratic voters on Election Day prefer a nominee who can beat Trump over someone who agrees with them on the issues.

That number is even higher in Washington state, where almost 7 in 10 said they want someone who can best Trump.

Candidate qualities

For those casting a ballot in Mississippi and Washington, uniting the country was the top quality they were looking for in a nominee. Biden won more than 9 in 10 of those voters in Mississippi and nearly two-thirds in Washington. He also soundly beat Sanders among Mississippi voters for whom bringing needed change and for whom caring about people like them were qualities that mattered, but Sanders bested the former vice president among Washington voters who wanted change.

For Michigan voters, having a nominee who could bring needed change was most important, and more than half thought Sanders was the man for the job. Missouri voters also prioritized a candidate who could bring needed change but split fairly evenly between Sanders and Biden. In both states, voters looking to unite the country and for a nominee who cares about them selected Biden.

The union vote

Biden won the backing of voters in union households in Michigan and Missouri, handily beating Sanders. About 3 in 10 voters in Michigan and a quarter in Missouri belong to a household with a union member.

Both candidates have played to unions during the campaign, with Biden warning that his rival will take away organized labor's hard-fought health care coverage through "Medicare for All," which would institute a national, government-run insurance program and essentially eliminate private policies. Biden, on the other hand, supports adding a government-run option to the Affordable Care Act exchanges.

Sanders countered by attacking Biden for his support for free trade deals, including the North American Free Trade Agreement, a sore subject for many Michigan residents who saw their auto industry jobs move to Mexico.

While the United Auto Workers union did not endorse a candidate, a former union president announced he is backing Sanders.

Biden also captured a majority of votes among non-union households in Michigan and roughly half of those in Missouri. Sanders won less than half in both states.

Union support was also an issue last month in Nevada, where leaders of the influential Culinary Union made it clear that they did not support Medicare for All. Still, Sanders earned the biggest share of union votes, though the field was split among more candidates at the time.

CNN exit polls were conducted by Edison Research for the National Election Pool in four states voting on March 10. Results are based on interviews conducted throughout the day with randomly selected Democratic primary voters at voting locations in Michigan, Missouri and Mississippi. Results in these states are reflective only of those who cast ballots on election day. In Washington, a telephone poll was conducted to interview those who vote by mail.

The margin of error for results based on the full sample is plus or minus 4 points in Michigan, Missouri and Washington and plus or minus 5 points in Mississippi.