Selecting variables to study You have selected the following prediction to test: Previously thinned forests will have higher tree survival than adjacent forests that were not thinned. Now you need to define the key variables that you will use to test this prediction. For the following variables, sort them as independent variables, dependent variables, or variables that should be controlled (held constant). See the hints for more information about variables. View Available Hint(s) Reset Help thinning or no thinning before the fire elevation of the site dominant tree species tree survival rate after the fire Independent variable | | Dependent variable Controlled variable thinning or no thinning before the fire elevation of the sitedominant tree species tree survival rate after the fire Independent variable Dependent variable Controlled variable