You have two flasks with borth media. One contains a species of cyanobacteria. The other flask contains E. coli. Both flasks are sealed and incuabated under optimal growth conditions for two days. Assuming the cell volume and metabolic rate of the bacterial cells is identical in each flask, why would the carbon dioxide concentration to be higher in the E. coli flask than in the cyanobacteria flask after the two-day incubation.