Which of the following is an example of an ecosystem? A) All of the brook trout in a 500 hectare2 river drainage system. B) The plants, animals, and decomposers that inhabit an alpine meadow. C) A pond and all of the plant and animal species that live in it. D) The intricate interactions of the various plant and animal species on a savanna during a drought. E) Interactions between all of the organisms and their physical environment in a tropical rain forest.