Answer:
Endosymbiosis
Explanation:
The endosymbiosis concept explains that the origin of membrane-bound organelles present in the eukaryotes occurred when some prokaryotic organisms started a symbiotic association with another prokaryote. Accordingly, mitochondria evolved when an anaerobic prokaryotic cell acquired aerobic bacteria as a symbiont. The symbiont lived inside the host cell and the host cell could form the process of aerobic cellular respiration. The purple bacteria are supposed to be the endosymbiont involved in the origin of mitochondria.
