FILE- In this Nov. 8, 2016 file photo, people vote at a polling place set up at the Kenter Canyon Elementary School in Los Angeles. California's primary election on Tuesday, June 5, 2018, includes races for governor, U.S. Senate and other statewide offices, all 53 U.S. districts and most seats in the Legislature. (AP Photo/Nick Ut, File)

FILE- In this Nov. 8, 2016 file photo, people vote at a polling place set up at the Kenter Canyon Elementary School in Los Angeles. California's primary election on Tuesday, June 5, 2018, includes races for governor, U.S. Senate and other statewide offices, all 53 U.S. districts and most seats in the Legislature. (AP Photo/Nick Ut, File)

California’s primary election is Tuesday and includes races for governor, U.S. Senate and other statewide offices, all 53 U.S. House districts and most seats in the state Legislature. The top two vote-getters in each contest will advance to the November general election, regardless of their political party. Californians also will vote on five propositions placed on the ballot by the Legislature.

Here are some key things to know:

VOTER TURNOUT

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More than 2.1 million Californians already have voted by mail as of Saturday, according to public data from counties compiled by the nonpartisan Political Data Inc. The organization’s vice president, Paul Mitchell, expects 70 to 75 percent of all primary votes will be cast by mail. He anticipates around 6 million people — about a third of registered voters — will cast ballots in the primary. That would be a low turnout but still better than the 25 percent who voted four years ago.

VOTER REGISTRATION

More than 19 million Californians are registered, according to the secretary of state’s office. That’s more than 75 percent of eligible voters. About 44 percent are registered Democrats. For the first time, Republicans are the third largest bloc at 25.1 percent, while 25.5 have no party preference. Five percent are registered with another party. This is the first year Californians who did not register by the May 21 deadline to vote in the primary can conditionally register at a county elections office or other designated location. Voters registered conditionally can cast provisional ballots, which take longer to process.

VOTE-BY-MAIL CHANGES

Under a new law, all registered voters in Sacramento, San Mateo, Madera, Nevada and Napa counties were mailed ballots. They can mail them back, put them in county drop boxes or vote in person at county vote centers, which have replaced polling places in those counties. A state law that allows ballots to be counted if they are postmarked by Election Day and received within three days has further delayed the final vote tallies. It often takes days and sometimes weeks to learn the outcome of close races.

OF INTEREST

— Recall elections are rare, but there are two high-profile efforts this primary. Republicans targeted Democratic state Sen. Josh Newman, of Fullerton, because of his vote last year to increase gasoline taxes, while Santa Clara County Superior Court Judge Aaron Persky could lose his job because of the light sentence he gave a former Stanford University swimmer for sexually assaulting an intoxicated woman.

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— Los Angeles-area voters may be surprised to see former state Sen. Tony Mendoza on the ballot. The Artesia Democrat resigned in February amid allegations he sexually harassed women who worked for him but then ran for the same seat.

— Mendoza’s old district is one of three in the L.A. area where voters are choosing candidates after lawmakers quit following sexual misconduct accusations. In special elections that coincide with the statewide primary, voters will choose replacements for former Democratic Assemblymen Matt Dababneh and Raul Bocanegra.

— The state insurance commissioner’s race includes one candidate — Steve Poizner — who once held the job as a Republican and is now running as an independent and another — Dr. Asif Mahmood — who started out running for lieutenant governor and then switched races.

— For the second straight election, Republicans aren’t expected to get a candidate into the runoff for U.S. Senate. Incumbent Democrat Dianne Feinstein is a heavy favorite, and state Sen. Kevin de Leon is expected to finish second. The 11 Republicans running are all little-known and have little money, and none received the backing of the state party.