In the United States, voters in six states are participating in primary elections that will set up the final races in November’s critical midterm elections.Tuesday is one of the busiest primary days of the year, with voting under way in Iowa, Montana, New Mexico, New Jersey, South Dakota and California.Recommended Stories list of 3 itemsend of listCandidates for no fewer than 74 seats in the US House of Representatives are on the ballot today, as voters decide who will progress to November’s general election.Tuesday’s outcomes could shape the political landscape for the remainder of President Donald Trump’s second term, as frontrunners are decided for the midterms.At stake is control over Congress. All seats in the House of Representatives, and roughly a third in the Senate, will be on November’s ballot. Democrats are hoping to win majorities in both chambers and wrest control back from the Republicans.Primaries generally allow voters to pick which Democratic and Republican candidates advance to a face-off, though there are variations on the format.In California, for instance, most statewide primary races are nonpartisan, and the top two vote-getters from any party move forward to November.So what’s on the ballot this Tuesday? Here’s a breakdown of the races.What …