Final answer:
Without specific data from case study 9, one would assume that the control group (untreated cells) would exhibit normal cell cultures with normal mitotic behavior.
Step-by-step explanation:
The question provided does not contain sufficient specific information from case study 9 to determine which level of treatment (low, medium, high, or control group) produced cell cultures with normal mitotic behavior. However, typically, a control group in an experiment is the standard by which tests are measured. The control group would usually consist of cells that have not been exposed to the treatment compound and therefore would maintain normal mitotic behavior assuming no other factors have affected them. So, unless additional data from the case study indicates otherwise, the control group might be expected to exhibit the most normal mitotic characteristics compared to treated groups.