Answer:
Endosymbiosis theory: It confirmed a fundamental prediction made by the hypothesis and have great evidences and could not be explained by any alternative hypothesis.
Step-by-step explanation:
Both bacteria and mitochondrial DNA are in circular form.
Both bacteria and mitochondria contain 70S chromosome, both have their own replicating machinery.
According to endosymbiosis theory :
The host cell provided a protected environment and carbon compounds for the endosymbiont; and in return ,the endosymbiont provided increased ATP from the carbon compounds.