I think the yellow arrows show a guide were it goes or maybe tissue fluids!
Yes, c because you can cross out protein because thats healthy and you cant really increase carbohydrate and c fat is the most unhealthy one so. and also fat is what makes you gain weight say theres to much "fat' in food.t
Gyri form the top of the ridges, while sulci form the " valley" of the ridges.
