As Bernie Sanders exits the race for president, here are 5 takeaways from CBS News exit polls and primary polls and how Joe Biden became the presumptive nominee. The last polls were conducted for the March 17 primaries.

1. Electability, handling a crisis, a return to Obama policies: Advantage Biden

Defeating President Trump was a priority for Democratic primary voters throughout the primaries. In every state where polls were conducted, voters prioritized electability in the general election over agreement on issues in a nominee.

In the states where voters were asked directly — which Democratic candidate would have the best chance of defeating Trump — Biden was the top candidate in each state except Vermont and Colorado (states Sanders won). In California — where Sanders came out on top - Biden and Sanders tied on this.

Many primaries were postponed because of the coronavirus outbreak. In the states where polling was done as the effects of coronavirus outbreak were beginning, Biden was favored over Sanders as the candidate trusted most to handle a major crisis, including in the key states of Florida and Michigan.

A desire for unity played a role too. Democratic voters who wanted a candidate who can unite the country went big for Biden. And Biden was helped by an electorate that was more inclined to prefer a return to President Obama's policies than a move toward more liberal policies. Biden won a majority of voters who were seeking a return to Obama era policies.

2. Biden's coalition: Black voters, moderates and older voters

Biden was able to build a winning coalition with strong backing from black voters, political moderates and older voters.

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The former vice president was the top choice of black democratic primary voters in all states where polls were conducted and by wide margins. His support among black voters in South Carolina helped bring Biden his first primary win and represented a turning point in the campaign.

Part of Biden's winning coalition was politically moderate voters. And while Sanders won the support of voters calling themselves "very liberal," Biden narrowly won the support of "somewhat liberal" voters.

Women voters (including suburban women) were more likely to back Biden, while men were more split. Across the primary states, 37% of men supported Biden, while 35% went for Sanders.

As they did in 2016, young voters supported Sanders by wide margins, but it wasn't enough to overcome Biden's advantage with other voter groups.

3. Biden swung some 2016 Sanders vote groups his way

In addition to his strong performance with black voters and older voters, perhaps more importantly, Biden was able to win some voter groups that backed Sanders four years ago, particularly in Michigan where Sanders won the primary in 2016 and a state that will likely be a battleground in November.

Voters living in union households made up three in 10 voters in Michigan and a quarter in Missouri. In 2016, Sanders won these voters – albeit narrowly in Michigan. Those voters swung Biden's way this time — he won union households by healthy margins in both states.

Biden's level of support among black voters was similar to Hillary Clinton's in many states four years ago, but he won a larger share of the white vote then she did in some key places. Sanders won white voters in Michigan four years ago, but more than half of their votes went to Biden this time.

In Michigan, Biden's support among white voters cut across education levels. He won the support of both whites with a college degree and those without.

Four years ago, white men without a college degree in Michigan voted for Sanders, but Biden made big inroads with this group, narrowly edging out Sanders among them.

Across all the primary states where polls were conducted, Biden beat Sanders among whites without a college degree. Sanders defeated Clinton among this group four years ago.

4. Hispanics, young voters: Advantage Sanders

Sanders did well with two groups that Democrats want to mobilize in November: Hispanics and young voters.

Sanders performed better with Hispanic voters this year compared to the 2016 primaries. In Nevada, Texas and California, a substantial share of the Democratic electorate was Hispanic. Sanders won the Hispanic vote in each of these states.

Young voters were some of Sanders' strongest backers; Biden had little traction with this group. This pattern is similar to the 2016 primaries when Hillary Clinton did not get much support among young voters. Months later, in November, her winning margins among young voters in states like Michigan and Pennsylvania were narrower than Barack Obama's in 2012.

5. What will Sanders voters do?

We don't know for sure what Sanders supporters will do in November, but most Democratic primary voters typically get behind a party's nominee. More than eight in 10 of Sanders primary voters said they would vote for the nominee regardless of who it is, while 15% said they would not. Those who indicated they may not get behind the nominee are more likely to be men and a bit younger than the Sanders backers who said they would back the nominee no matter who it is.

This analysis is based on CBS News exit polling and primary polls conducted during the primary campaign. Polling was conducted in 23 states. Not every question was asked in all 23 states.