What is one instance where sunlight is not the source of energy for a food chain/web?

I would say it would be for animals. only grass and trees need sunlight as "food" or to help them. regular animals dont need sun to eat. hope this helps

Well i don't how much this helps but if we had enough vitamins to give us energy we wouldn't need the sun i guess that's one instance

Ibelieve the answer is relative humidity  because it makes more sense that way. solar flares usually occur in space it doesn't affect the earth, well it could but it wont make a significant damage.  latitude is land it doesnt do anything. prevailing winds, i dont know the correct meaning for this but i doubt that affects the land so it has to be relative humidity.