In an experiment to determine whether green plants take in co2, a biologist filled a large beaker with aquarium water to which she added bromothymol blue

QUESTION:
In an experiment conducted to determine whether green plants take in CO2, a biologist filled a large beaker with aquarium water to which she added 
bromothymol blue. She exhaled CO2 into the solution of bromothymol blue, which made the solution turn yellow. Then she placed a sprig of Elodea into two test tubes. She left a third test tube without Elodea to serve as a control. She added the yellow bromothymol solution to all three test tubes and placed a stopper in each. Next, she placed all the test tubes in sunlight. After several hours in sunlight, the bromothymol solution in the test tubes with the Elodea turned blue. The bromothymol solution in the control remained yellow. What conclusion can be drawn from the experiment? Explain

ANSWER EXPLAINED:

That the test tubes with bromothymol solution took in the carbon dioxide which make them turn blue. So that concludes that green plants take in carbon dioxide.

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