Final answer:
The organelles involved in the endosymbiosis theory are mitochondria and chloroplasts, which were once free-living bacteria engulfed by larger host cells.
Step-by-step explanation:
In the endosymbiosis theory, the organelles involved are mitochondria and chloroplasts. This theory suggests that these organelles were once free-living bacteria that were engulfed by a larger host cell. Over time, a symbiotic relationship developed, with the host cell providing protection and nutrients to the organelles, and the organelles providing energy through processes such as respiration or photosynthesis.
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