1. **Stating the problem:** Determine whether CO₂ is produced or consumed when Elodea is placed in light or dark environments for 24 hours based on color changes in test tubes. 2. **Hypotheses:** - In light, Elodea will consume CO₂ due to photosynthesis. - In dark, Elodea will produce CO₂ due to respiration. 3. **Explanation of variables:** - Independent variable: Light or dark environment. - Dependent variable: CO₂ concentration indicated by color change. 4. **Data interpretation:** - Test tubes with orange to pink color indicate CO₂ consumption (less CO₂). - Orange to yellow indicates CO₂ production (more CO₂). 5. **Controls:** - Tubes #1 and #3 stayed orange, serving as controls to show no change without Elodea or light. 6. **Tube analysis:** - Tube #1: No change, control. - Tube #2: Color changed from orange to pink, indicating CO₂ consumption in light. - Tube #3: No change, control. - Tube #4: Color changed from orange to yellow, indicating CO₂ production in dark. 7. **Claim:** - CO₂ is consumed in light. - CO₂ is produced in dark. 8. **Evidence:** - Tube #2's pink color shows CO₂ decrease. - Tube #4's yellow color shows CO₂ increase. 9. **Reasoning:** - Photosynthesis in light uses CO₂, lowering its concentration. - Respiration in dark produces CO₂, increasing its concentration.