Final answer:
The greater color change in the bromothymol blue experiment indicates an increased rate of production of carbon dioxide.
Step-by-step explanation:
The greater color change in the bromothymol blue experiment when running indicates an increased rate of production of carbon dioxide. Bromothymol blue is an indicator that changes color in the presence of certain substances, and in this experiment, it changes from blue to yellow when exposed to carbon dioxide. Therefore, option D, carbon dioxide, is the correct answer.
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