The endosymbiotic theory was supported by the scientist carl woeselynn margulisrobert hook, who studied mitosing cells.

Lynn Margulis supported the endosymbiotic theory and studied mitosis in cells. She was an American evolutionary theorist who made great significance in the symbiosis of organisms in biological evolution. She is also a developer of the Gaia Theory, which believes that the Earth functions as a single self-regulating system. 

The person from this group of peope who was the one that supported the so called endosymbiotic theory was named Lynn Margulis, as she was also the one of these who did studies on mitosing cells. She is a known evolutionary theorist who was responsible for certain key advances and open discussion of this theory.