Biology OCR past paper question help.

One theory about the evolution of organelles is the endosymbiotic theory. This theory suggests that the mitochondria and chloroplasts found in eukaryotic cells represent formerly free-living bacteria that were absorbed into a larger cell.
The following list describes a number of features of mitochondria and chloroplasts.
Place a tick (✓) next to the three statements that could be used as evidence for the endosymbiotic theory.

Could someone explain why the answer is

mitochondria contain ribosomes that are smaller than those found in the cell cytoplasm

mitochondria are a similar size to bacteria

chloroplasts have their own circular DNA

I don’t remember this information being in the content we learned.

Reply 1

alexpenberthy

Mitochondria contain smaller ribosomes, which are also found in other prokaryotes, suggesting that they too were one free living prokaryotes. Eukaryotes tend to have larger ribosomes instead.

Mitochondria are a similar size to bacteria, again suggesting that they could have been free living bacteria, as they are a viable size to survive.

Chloroplasts have their own circular DNA. Circular DNA is not found in the nucleus of plant cells (they have double stranded DNA), only in the chloroplasts. Bacteria also have circular DNA, so circular DNA is evidence that links chloroplasts to bacteria.

I hope this helps!! If anyone else knows better feel free to correct me