Mitochondria and chloroplasts likely evolved from engulfed bacteria that once lived as independent organisms. ... Eukaryotic cells containing mitochondria then engulfed photosynthetic bacteria, which evolved to become specialized chloroplast organelles.
The answer is prokaryotes
1,203,375 different species of animals on earth and 1,589,361 different species of plants on earth (so your answer is more)
One factor is resting and exercising
stress and peace
Most, maybe all, bacteria have their genome DNA tethered to their cell membranes, so it is in the cytoplasm but its not really floating around. Plasmids in bacteria however are free floating. This is why it's so easy to isolate plasmids from bacteria with centrifugation after lysing.
