This is false. Organisms may play several important roles in an ecosystem. Consider for example and ocean shore environment occupied by a particular species of crab. The crabs are scavengers and eat any organic matter they encounter. They therefore play an important role in the cycling of nutrients in the ecosystem. The crabs are however also an important source of food for a range of other species occupying the same habitat, including octopi, certain fishes and sea otters. Therefore, the crabs are an important part of the food web in the ecosystem. Many species similarly occupy multiple important roles in an ecosystem.
True. By the name itself, those are the things they are supposed to do.
Je ne peux pas vraiment expliquer la réponse en raison de votre question confuse, mais voici une note pour faire des questions non confuses la prochaine fois
Answer: Laws passed by Congress and State and local governments
Hope this helps!