One urn, U1, contains one blue ball (labeled B1) and three red balls (labeled R1, R2, and R3). A second urn, U2, contains two red balls (labeled R4 and R5) and two blue balls (labeled B2 and B3). An experiment is performed in which one of the two urns is chosen at random and then two balls are randomly chosen from it, one after the other without replacement. (a) Construct the possibility tree showing all possible outcomes of this experiment.