Test Tube D Experiment

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Bromothymol blue (BTB) is a pH indicator that has a color of yellow in acidic state, blue in basic state, and green in neutral state. The experiment that Rosa did is to find what species do photosynthesis and/or cellular respiration by observing changing in pH level in the water due to biological processes of living organisms in different tubes. The tube D is the control that had no variable added. So, it shows that the water with BTB would stay same, the basic state in the blue color. Test tube A had a water snail, and after an hour, the BTB changed to yellow which means there was a some type of process that turned basic water to acidic. A water snail does cellular respiration because all living organisms do cellular respiration to absorb