They work together to achieve the maximum results of protein synthesis, protection against diseases, and cleansing accumulated toxins.
Dark Green vegetables are high in antioxidants like indoles (phytochemicals related to cancer prevention) and lutein which protects the eyes, skin, and heart. They also supply the most vitamins and minerals so desperately lacking in most diets.
Why not eat greens is the real question. Greens are low in calories, high in biophotons, and micronutrients with few if any carbohydrates. Some contain natural sugar content but not a huge amount. Green leaves can rid the body of carcinogens, reduce the incidence of inflammation and stimulate immune cell production.