A student is studying the effects of several solutions on the prevention of the browning of apples. the student used solutions having different ph values and immersed three apple slices in equal volumes of each of the solutions. which of these is the independent variable in this investigation?

Based on the variables that are used or stated on the problem, I think the independent variable in this investigation is the ph of the solution. Independent variable is a type of variable that is being manipulated in the experiment. Somehow, you are testing their effects on something. So base on the problem, the variable is being manipulated is ph of the solution.