Which automatic system conserves energy by returning the body to a normal activity level through a lowered heart rate and blood pressure?
a. peripheral nervous system
b. sympathetic nervous system
c. somatic nervous system
d. parasympathetic nervous system

The higher you go up the less oxygen there is 

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.