cyanobacteria were the first photosynthetic organisms. How were they responsible for allowing higher life forms to evolve? A:They released oxygen, which mixed to form iron, and later ferrous oxide, in the air. B: They released carbon dioxide, which evolving animals needed. C: They released oxygen, which created the ozone layer, which resulted in reduced mutation rate.

Question

raspberryjam · Answer

The key word here is that they are photosynthetic organisms. Do you remember the equation for photosynthesis and what it produces? Based off of that equation you should be able to find your answer :D