Respuesta :
The controlled variable is kept constant during the whole experiment in all the different study groups. In this experiment, Sodium bicarbonate solution is the controlled variable.
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During an experiment, the controlled variables are kept constant in the control groups and the experimental groups. Unlike the independent variable, the controlled variables do not influence the results. These variables do not affect the response of the dependent variable.
In this experiment,
- The independent variable → presence/absence of light reaching the plant. The researcher regulates the amount of light by using different elements such as the bucket, lamp, flashlight, and natural light.
- The dependent variable → oxygen production through which the researcher measures the photosynthesis rate.
- The controlled variable → Sodium bicarbonate solution. It provides carbon dioxyde, and must be constant in the four scenarios to avoid an effect on the results.
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