Explain the role of diet and exercise in physical fitness and development

Diet is necessary to get all the required  nutrients that your body needs..

and physical fitness is necessary to maintain the level of all the nutrients like there should not be any kind of extra amount of a particular nutrient like carbohydrates..protiens..etc..

in short we can say to keep you fit and healthyy..

you may having too much sleep.. a good night sleep consists of about 7 hours. more than that could be the reason you're still tired throughout the day.