The student clearly states the independent variable as pH levels and the dependent variable as the fermentation rate of Saccharomyces cerevisiae, establishing a relationship that can be investigated. However, the research question lacks a specific method of analysis, which should include details on how the fermentation rate will be measured. The student does not adequately explain the choice of pH levels or the sampling technique used in the experiment, nor do they discuss the rationale behind the number of trials and controlled variables. Despite these shortcomings, the student effectively identifies safety, ethical, and environmental issues associated with the investigation, and provides a detailed and coherent methodology that allows for reproducibility.
