To answer this question, I would need to know more details about the investigation in question. In scientific experiments, the independent variable is the factor that is deliberately manipulated or changed by the researcher to observe its effect on the dependent variable - the outcome or result we are measuring. For example, if you are conducting an investigation to determine how the concentration of fertilizer affects plant growth, the independent variable would be the concentration of fertilizer because the researcher is deliberately varying the concentration to observe its effect on plant growth. Without more information about the specific investigation, I cannot answer this question accurately.
