why is the combination of sound nutrition and regular physical activity the most desirable method of permanent weight control

Ihave a really high metabolism and only weigh 70 pounds (13 almost 14). people always ask me two questions: do you ever eat and how do you eat so much and stay so skinny. i am worried that a high metabolism wont me forever. what are some safe steps i can take to maintain being fit. (also, i already work out i am a dancer so i get cardio a lot)

Which of the following is not a fitness benefit of cycling a: very effective at burning fat b: provides an upper body workout c: provides an aerobic workout d: good exercise for out of shape people

When lifting heavy loads off the ground, the majority of the weight should be lifted by which of the following? a. arms b. legs c. back d. stomach