What different characteristic(s) exist between the two groups that allow for the different staining conditions?

What different characteristic(s) exist between the two groups that allow for the different staining conditions? Why was the Gram iodine was added to the Gram staining procedure? Why is a counterstain (safranin) added to the Gram staining procedure? What are the advantages of performing a Gram stain versus a simple stain for visualizing bacteria? Did you experience any technical difficulties or atypical results during this lab? If so, what happened? Why do you think they occurred? How could you avoid these issues in the future?