[填空题] Maintaining body health is one of the most important tasks in life. A healthy body requires (36)______foods and liquids for growth, development , and (37)______ against disease. A healthy body also (28 )______fresh air, exercise, and rest. Maintaining body health requires (39)______effort. You choose the foods you eat. You choose (40)______you get fresh air and exercise. You choose how much rest you get. Nutrition is one of the most important (41)______of body health. When people do not eat enough food or do not take in certain (42)______ nutrients, they can suffer from (43)______. Sometimes disease robs the body of the essential nutrients in the diet. This condition is called secondary malnutrition. (44)____________. Three essential substances which may come from foods are carbohydrates, fats, and proteins. Carbohydrates provide body fuel. Fats are stored in the body for future energy uses. Proteins are required for growth needs and for defending the body agains