Response variable is a dependent variable. It is dependent on the explanatory variable that is referred to as the independent variable.
In research study, the response variable is what is usually measured by the researcher. In the case given above, short-term memory is the response variable, which is dependent on exercise.
Andrew is wanting to build a slide for his daughter's tree house in the backyard. The tree house is approximately 5 feet off the ground and he wants the slide to have a 30 degree angle with the ground. He will need to by 10 ft of sliding board.