2.) a scientist is testing the efficiency of various ph levels by measuring average growth rate. she runs 7 trials. what is the dependent variable of this experiment? a.) plant growth b.) ph of soil c.) average plant growth d.) type of soil

I think it's B because in the question it says "she is testing the efficiency of various pH levels by measuring average growth rate". Also, keep in mind that dependent variable is what is being tested or measured in a scientific experiment. The growth of the plant would be independent variable because when testing for a independent variable it's the change or what's being controlled.