A Food Chain Without Herbivores and Carnivores. Without the herbivores, the producers would be free to grow. Producers don't need the herbivores or carnivores to make their own food and energy. They are self-sustaining, and they can't exhaust their food source.
And as well as if there are only producers and no herbivores or carnivores then producers grow on continuously and there will not be the utilization of it. so there can't be a food chain without herbivores or carnivores.
Answer:
They have a backbone, most use legs,wings,or fins for movement.
Villi increases the surface area to help with absorption and digestion. Micro-villi form a brush border that vastly increases the surface area of the plasma membrane so larger amounts of nutrients can be absorbed.