Which statement best compares coral reef ecosystems to demersal ecosystems?

coral reef ecosystems have high levels of nutrients in the water, and demersal ecosystems do not.
coral reef ecosystems are typically in shallow water, and demersal ecosystems can exist at any depth.
coral reef ecosystems can support large fish like sharks and rays, and demersal ecosystems cannot.
coral reef ecosystems may have starfish, clams, and other invertebrates, and demersal ecosystems have only fish.