I’m kind of smart of anything

That's cool.

I wonder if you could answer a biology question?

Someone please help. I can't figure this out.

All organisms are dependent on a healthy carbon dioxide-oxygen balance. Photosynthesis and cellular respiration are key processes in maintaining this. Your class is conducting a lab experiment to investigate the relationship between photosynthesis and cellular respiration by observing how carbon dioxide cycles through a biological system.

To conduct the experiment, each group set up four test tubes containing 30 ml distilled water and 3 ml of bromothymol blue. Bromothymol blue is a pH indicator that changes from blue (alkaline) to yellow (acid). When carbon dioxide dissolves in water, it produces carbonic acid, turning the indicator from blue to yellow. The level of CO2 was inferred from a change in the indicator color.

A snail, elodea (aquatic plant), or both were added to the tubes and they were stoppered. Tubes were placed under a grow light for 24 hours and the results recorded. The test tubes were then covered for 24 hours to produce a dark environment and the results recorded. Which statement best explains the change in Test Tube D from the light setup to the dark setup.

Test Tube Contents  Initial ColorLight Set Up  Dark Set Up

Tube A: control          green         green          green

Tube B: elodea          green         blue                  green

Tube C: snail                  green         yellow          yellow

Tube D: elodea & snail  green         green          yellow

A)The rate of photosynthesis decreased in the dark, thus the elodea used less CO2. The elodea and snails produced less CO2 through cellular respiration, causing the CO2 to be in equilibrium, making the solution more neutral (yellow).

B)The rate of photosynthesis decreased in the dark, thus the elodea used less CO2. The elodea and snails continued to produce CO2 through cellular respiration, raising the level of CO2 in the tube, causing the solution to become more acidic (yellow).

C)The rate of photosynthesis decreased in the dark, thus the elodea used more CO2. The elodea and snails continued to consume CO2 through cellular respiration, lowering the level of CO2 in the tube, causing the solution to become more basic (yellow).

D)The rate of photosynthesis decreased in the dark, thus the elodea used less CO2. The elodea and snails continued to consume CO2 through cellular respiration, raising the level of CO2 in the tube, causing the solution to become more acidic (yellow).

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