16. Populations can grow when needs are in met But when populations in an ecosystem have the same needs and utilize the same resources, the resource becomes scarce and competition exist 17 any relationship that involves two or more species living and interacting together, A Symbioses B Food chain C. Food web 18 is composed of interconnected food chains. Energy and materials in the food chains circulated within ecosystem A food web shows the multiple interactions among the different types of organism. A Symbioses B Food chain C. Food web 19. is the linear series of organisms illustrating a one-way route of feeding relationship. Food energy is passed from one organism to another through a sequence of events. It always begins with producer (plants) since they can make their own food and then they are eaten by a series of consumers. C. Food web A Symbioses B. Food chain 20 Organisms that make their own food. A. Producers B. Consumers C Decomposers​