Question

what do we think mitochondria used to be? what evidence is this belief based on? former parasites; evidence from their unique structure and function. independent bacteria; evidence from binary fission, dna, and ribosomes extracellular components; evidence from their role in energy production. ancient viruses; evidence from their ability to replicate.

Explanation:

The endosymbiotic theory posits that mitochondria were once independent bacteria. Evidence includes their ability to divide by binary fission like bacteria, having their own circular DNA similar to bacterial DNA, and possessing ribosomes with a size and structure like those of bacteria.

Answer:

Independent bacteria; Evidence from binary fission, DNA, and ribosomes