Leticia timed how fast apple slices turned brown after being dipped in different preservatives, such as lemon juice, fruit juice freshener amd lime soda. What is the Independent Variable and what's the Dependent variable?

Independent variables are those variables whose dependence on other variables does not exist. Dependent variables are those variable that are functionally related to the independent variables. Example, in the experiment where the amount of ice and the time that amount takes to become water by melting, has the amount as the independent variable and the time of melting as the dependent variable. In this experiment the,

Independent variables are the choice of liquid or juice.

Dependent variable is the time elapsed for the browning of the slice of apple.