A general rule relating the capacity of a specific animal's digestive system to provide adequate access to substrates for biosynthesis of cellular components, as well as fuel molecules needed for ATP production, is that the animal should have access to

A) a high-protein, low-carbohydrate diet.
B) a diet low in lipids and high in protein.
C) a low-calorie diet with a large intake of fluids, especially water.
D) a diet that matches the "food pyramid" for the species.
E) a diet that maximizes vitamins and minerals.