The pH indicator bromothymol blue is blue in an alkaline solution and yellow in an acidic solution. A slight increase in acidity, such as when CO2 gas is added, causes a solution with the indicator to change from blue to yellow.


A solution with the indicator would be most likely to turn from yellow to blue when which combination of factors exists?


Select the two correct answers

A. a person blows air into the solution through a straw.

B. algae in the solution are placed under a bright light.

C. a water plant in the solution is placed on a sunny windowsill.

D. yeast cells and sugar are placed in the solution.