Charlie is trying hard to lose his "spare tire" before his wedding. He has two months to get ready for the event. He decides to go about his weight loss systemically. The first week, charlie exercises vigorously. The second week, he gives up meat. The third week he drinks large amounts of water. The fourth week, he eats just bananas. He continues to vary his approach each week. At the end of his eight-week experiment, he concludes that his best weight loss comes from exercise. Identify the independent and dependent variables in this scenario.