The theory suggests that favorable behaviors are passed down from generation to generation.
optimality
natural selection
adaptation
optimum

The optimality theory is the theoretical concept that states that behaviors that a fit is the behaviors that are passed thru generations. Although, behavior is subjected to change due to various factors such as the environment, culture, norms and other sociological elements. The natural selection theory in contrast is different, different in the sense that natural selection happens when an organism is forced to adapt due to certain selection forces.

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.