This ancient trick for processing CO2. Plate tectonics, oxygen, and Rubisco. Cool ancient biochemistry.

There seem to be a lot of recent articles about the origins of life, oxygen, and related topics. With some fascinating debates and discoveries. https://scitechdaily.com/zircons-unlock-earths-early-history-life-sprung-from-a-stagnant-lid-not-plate-tectonics/

https://scitechdaily.com/ancient-source-of-oxygen-for-life-discovered-hidden-deep-in-the-earths-crust/
I am throwing these all together but not trying to explain the links because the research goes in a lot of directions.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7610757/
This is really amazing, because some researchers are figuring out faster ways of fixing CO2 using this ancient molecule.

Interview unfortunately with broken photo links. https://theplosblog.plos.org/2018/10/looking-for-the-origins-of-life-using-synthetic-biology-an-interview-with-betul-kacar/

Background on how some organisms killed off all the others with oxygen: https://en.wikipedia.org/wiki/Great_Oxidation_Event

https://phys.org/news/2023-06-theory-earth-oxygen-rich-atmosphere-late.html
As I said above, I am just discovering this stuff, so I am not going to try to explain things. This appears to be another of the many theories being tested for explaining where we got so much oxygen. Hopefully this is exciting stuff to find out more about.

Only small stars give planets time to evolve oxygen which makes high energy animal life possible, and hence intelligence, or something like that.