Final answer:
Starch and dietary fiber are classified as complex carbohydrates. Starch is made by plants to store energy, while fiber is an essential nutrient with physiological roles.
Step-by-step explanation:
Starch and dietary fiber are classified as complex carbohydrates. Carbohydrates are organic compounds made up of simple sugars. Starch is a complex carbohydrate that is made by plants to store energy. Dietary fiber, such as cellulose, cannot be digested by the human digestive system and is considered an essential nutrient for its physiological roles.