which mixtures of bacterial species can form biofilms. To determine this, you perform a bacterial growth study looking at the number of viable bacteria cells remaining after treatment with penicillin (an antibiotic). You know that all your mixtures of bacteria are susceptible to penicillin when they do not grow as a biofilm. You include a control mixture in your study that you know does not form biofilms. Three different experimental mixtures (Groups 1, 2, and 3) and your control were grown at the same density of cells (12,000 cells per dish). You treat all groups with the same dose of penicillin for 10 hours. You count the number of viable cells 6 hours and 48 hours after the treatment ends. The graph below shows the data from this experiment. Graph depicting average number of cells (10^3 cfu/mL) on the x-axis over time on the y-axis of Control and three variable groups. Sharp decline of all groups until hour 6, then steady decline of Control, Group 1, and Group 3 until hour 48, and steady incline of Group 2 until hour 48. Which of the bacterial mixtures(s) grow as a biofilm? Group 1 Group 2 Group 3 Groups 1 and 2