Bromothymol blue (BTB) is a pH indicator that is used to detect carbon dioxide (CO2). It starts as a green color when the pH is neutral but turns blue when the pH is basic and the CO2 is low, and turns yellow when the pH is acidic and the CO2 is high. A group of students conducted an experiment using two test tubes that were set up according to the table below. They placed both test tubes under an ultraviolet lamp and monitored the color change over a 24-hour period. What is the most logical observation that will be seen at the end of the 24 hours, and why?