Justin B. believes that the temperature lowering during the fall months is what causes the color of the leaves to change. He set up an experiment wherein he placed some plants in 80 degrees rooms and some in 60 degree rooms. He then observed the color of the leaves for a total of 1 month. At the end of the month Justin observed that ¾ of the plants in the 60 degree. what is the control group, independent variable and dependent variable ?