The best fossil evidence suggests that life began 4 billionyears ago. But free atmospheric oxygen didn't really peak untilabout 2.5 billion years ago. Multicellular animals did not ariseuntil about 600 million years ago. While there is some evidence forphotosynthesis and biological creation of free oxygen much earlierthan that, it seems like much of the world was anoxic (without freeoxygen) for over a billion years of evolutionary time. Oxygen ishighly corrosive, and too much can be dangerous, even for thoseorganisms that evolved to require oxygen (like us!). Based on whatyou know, what reasonable hypothesis/predictions might you make(i.e., not looking for the \"truth\" - looking for testablepredictions!) as to why would the Atavistic Hypothesis predict thathigh levels of oxygen might be an effect treatment for tumors?SELECT ALL THAT APPLY.
A. High oxygen levels might not have a deleterious effect on MCgenes which seem to have evolved much later than the 2.5 billionyear oxygen rise.
B. We know that muscle cells can switch from aerobic toanaerobic physiological pathways, so neither of the other answersmakes much sense.
C. Multicellular organisms inherited the core unicellularreproductive genes/gene network with minimal modification.
