The movement of organic matter from the producer level through various consumer levels by the process of eating and being eaten is called food chain. In the process of photosynthesis, in the presence of sun, producers produce food, which is consumed by heterotrophs especially the herbivores who are further consumed by carnivores or omnivores. Detritivores and decomposers then release energy in the form of nutrients by feeding on the dead animals or dead organic matter. With these nutrients plants grow in the soil resulting in a complete energy or nutrient cycle. This is called the food chain.