Which observation is offered as evidence for the endosymbiotic origin of mitochondria?

1. Endosymbiosis is proposed to explain why mitochondria and chloroplasts contain DNA and ribosomes. 2. Bacteria, mitochondria and chloroplasts have long been noticed to be similar in size. 3. Bacteria have DNA and ribosomes, just as mitochondria and chloroplasts do. 4. That shared possession of a bacterial-style genome and translation machinery is the evidence offered. 5. Mitochondria are bounded by two membranes, not one, so that answer is factually wrong. 6. Chlorophyll is confined to chloroplasts, so it cannot be evidence about mitochondria. 7. The evidence is that mitochondria hold DNA and ribosomes as bacteria do. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 4 "Cell Structure", section 4.3 Eukaryotic Cells_