Answer;
C. if water plants take in co2, then the solution will turn from yellow to blue.
Step-by-step explanation;
-Bromothymol blue is a pH indicator that is mostly used in applications that require measuring substances that would have a relatively neutral pH. A common use is for measuring the presence of carbonic acid in a liquid or dissolved carbon dioxide.
-The indicator changes color over a pH range from 6.0 (yellow) to 7.6 (blue). It is a good indicator of dissolved carbon dioxide (CO2) and other weakly acidic solutions.
-Low levels of carbon dioxide or acid in solution with bromothymol blue indicator will appear blue. As the level of carbon dioxide or acid increases, the solution will gradually take on a yellow tint.