Which of the following must the investigator measure during an experiment?

independent variable

dependent variable <<<<<

controlled variable

correct

Thanks soooo much, I always doubt myself when I get really simple looking problems so then I start to over think it too much. At least I now know I should stick with the answer I first get :)

The investigator must measure the dependent variable during an experiment. The dependent variable is the variable that is being measured or observed to see how it changes in response to the independent variable. It is the outcome or the effect that the investigator is interested in studying. To measure the dependent variable, the investigator needs to collect data or observations that reflect its changes. This can be done through various methods such as taking measurements, conducting surveys, recording observations, or using instruments or sensors. The data collected on the dependent variable provides information on how it is influenced by the independent variable.