Natural selection could not occur without variation and acts on a

The theory of natural selection is one of the most influential scientific theories about the evolution of living organisms wherein it was first formulated by the famous Charles Darwin. It is described as the adaptation of an organism to an environment in order for it to survive with variation in its traits.

True, for example the gulf of mexico is surrounded by the us and spain& mexico.

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.