Multiple new polls on the presidential and U.S. Senate races in Iowa have their slight differences but overall indicate one thing: Both races are very close.The latest polls came from Monmouth University and Emerson College.On the presidential race in Iowa, the New Jersey-based Monmouth poll showed a true toss-up: Republican incumbent Donald Trump at 48 percent and Democratic challenger Joe Biden at 47 percent.When Monmouth adjusted its results for potential high voter turnout, it projected Biden sliding ahead, 50 percent to 47 percent.