Question

bromothymol blue is an indicator used to show the levels of co₂ in liquids. after bromothymol blue is added to a solution, if there is a large amount of co₂, the solution will turn yellow. when there is little to no co₂, the solution turns blue. two test tubes were filled with a solution of bromothymol blue. a student exhaled through a straw into each tube, and the bromothymol blue turned yellow. an aquatic green plant was placed into each tube, and the tubes were covered. one tube was placed in the dark, and one was placed in direct sunlight. the yellow solution in sunlight turned blue, while the one in the dark remained yellow. image of three test tubes: high co₂ (yellow), medium (green), low co₂ (blue) a student wants to investigate what will happen in the test tubes if a snail is also placed in the test tube. after several hours in the light, the test tube containing a snail and a plant has turned a greenish - blue color. what two conclusions can be made? (choose 2) a. both of these organisms require oxygen to live. b. the co₂ produced by the snail is being used by the plant. c. the plant is able to produce large amounts of oxygen through photosynthesis. d. the snail is able to use the co₂ produced by the plant to produce oxygen. e. the plant is able to neutralize the acidic bromothymol blue solution. f. the plant is performing photosynthesis and removing co₂ from the water.

Explanation:

1. Analyze Option B: Snails respire (produce \(CO_2\)) and plants perform photosynthesis (use \(CO_2\)). In the dark, the plant can't do photosynthesis normally, but with the snail producing \(CO_2\), the plant might use it (even if at a reduced rate), and the color change (greenish - blue) shows an intermediate \(CO_2\) level, suggesting \(CO_2\) from the snail is used by the plant.
2. Analyze Option F: The plant, even in the dark, might still perform some level of photosynthesis (or use \(CO_2\) in another way) and remove \(CO_2\) from the water. The color change from yellow (high \(CO_2\)) to greenish - blue (intermediate \(CO_2\)) indicates a reduction in \(CO_2\) levels, which can be due to the plant removing \(CO_2\).
3. Analyze Option A: The experiment is about \(CO_2\) and color change, not directly about oxygen requirement, so A is not a valid conclusion.
4. Analyze Option C: In the dark, plants can't perform photosynthesis to produce large amounts of oxygen, so C is wrong.
5. Analyze Option D: Snails respire and use oxygen, not produce oxygen from \(CO_2\), so D is wrong.
6. Analyze Option E: The color change is due to \(CO_2\) levels, not neutralization of the indicator solution, so E is wrong.

Answer:

B. The \(CO_2\) produced by the snail is being used by the plant.
F. The plant is performing photosynthesis and removing \(CO_2\) from the water.