Rick is a healthy 17-year-old high school student who is 70 inches tall and weighs 205 pounds. he has decided to "get a six-pack" over the summer with a diet and exercise program. as part of his new plan, he has stopped drinking soda and is eating more salads in addition to his usual diet. besides of these changes, he is unclear on how to proceed to reach his fitness goal. rick's mother wants to make sure his approach will not interfere with his normal growth and development, and has asked him to seek reliable information to him make a reasonable plan.