Answer:
Immunomagnetic cell separation, fluorescence-activated cell sorting (FACS) and density gradient centrifugation.
Step-by-step explanation:
Immunomagnetic cell separation, fluorescence-activated cell sorting (FACS) and density gradient centrifugation are the techniques used by the scientists to isolate cells and organelles from complex mixtures. Density gradient ultracentrifugation is a common technique used to isolate and purify biomolecules and cell structures so in my opinion Density gradient ultracentrifugation is the best method to isolate biological cell for this study.