A food chain is a network of links between organisms that are correlated with each other by the food they eat. It begins with the producer's and ends on the consumers' species, Each level of a food chain represents a different topic level. For example, grass which has been eaten by a grasshopper, which has eaten by a frog, which has been eaten by a snake and snake which at last, eaten by a hawk. And this is how energy is passed from the producers to consumers, and from consumers to decomposes