In a lab investigation of endosymbiosis, students test wheth…
In a lab investigation of endosymbiosis, students test whether the presence of a potential endosymbiotic bacterium affects ATP production in a eukaryotic host cell culture. They set up three groups of identical host cells: Group 1 is exposed to live bacteria, Group 2 is exposed to heat‑killed bacteria, and Group 3 receives no bacteria. All groups are kept at the same temperature, nutrient level, and light conditions, and ATP production is measured after 24 hours. Which option correctly identifies the independent variable, the dependent variable, and one controlled variable in this experiment?