Mitochondria and chloroplasts are thought to have been

Mitochondria and chloroplasts likely evolved from engulfed prokaryotes that once lived as independent organisms.
(At some point, a eukaryotic cell engulfed an aerobic prokaryote, which then formed an endosymbiotic relationship with the host eukaryote, gradually developing into a mitochondrion. Eukaryotic cells containing mitochondria then engulfed photosynthetic prokaryotes, which evolved to become specialized chloroplast organelles).

Im not sure if you still need this but the answer is 300 hz450 hz  i just did this lesson so , wish you the best of luck and take care