Don't see any graph but can surmise:
1. The line which rose dramatically prior to the Cambrian explosion-the time of the oxygen poisoning, must be oxygen. The line which concurrently fell must represent CO2.
2. Living cells increased oxygen and decreased CO2. <span>
3, oxygen diminished to an extent, CO2 increased, as cyanobacteria take in co2 and give off oxygen </span>
