SUN>if the sun goes away then all of the "producers" would die out,then the organism that rely on that "producer" would die then the organisms that rely on those organism would have nothing to eat and so on...
in this food web everything needs the sun to live but if the sun was to somehow go away then there would be no way for the producers to make food because then need sun for energy to go through photosynthesis. if the producers cant make their food then they will die. if all of the producers die then all the primary consumers would have nothing to eat. so on. then all of the animals that would rely on on the primary consumers would die out because their food source is gone.