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a/

1. Because a healthful lifestyle leads to a longer, happier, healthier life. (dồng đầu tiên)

2. Staying healthy means eating well-balanced diet, getting regular exercise, avoiding things that are bad for the body and mind. (Staying healthy means....mind)

3. Fat, sugar, salt. (Keep fat intake low. Eat foods high in carbohydrates, which....in vitamins)

4.  Tiredness, irritability, poor general health (Lack of proper physical exercise can cause tiredness...health)

5. aerobic exercise and muscle-strengthening exercise (Physical fitness requires both aerobic exercise, such as running, bicycle riding, and swimming, and muscle-strengthening exercise, such as weight-lifting)

6. weight-lifting (...muscle-strengthening exercise, such as weight-lifting)

7. Yes, it is. (A healthful lifestyle leads to a longer, happier, healthier...)

b/ 

8. running, bicycle riding, swimming (Physical fitness requires both aerobic exercise, such as running, bicycle riding, and swimming)

9. carbohydrates (Eat foods high in carbohydrates, ưwhch are the starches in grains...fruits)

10. vitamins (Eat lots of fruits and vegetables which are high in vitamins)