During an experiment, the student measured the initial concentrations of O2 and CO2 in three flasks, added organisms to some of the flasks, sealed the flasks, and placed them under a light. After 12 hours, the student measured the concentrations of O2 and CO2 in the flasks. The results for each flask are shown in the table.
During the experiment, the student had forgotten to identify the contents of each flask. Each of the three flasks contained one of the following: two plants and one insect; one insect; or no organisms.