The arrows between the circulatory system and respiratory system show . The arrow going from the respiratory system to the circulatory system shows .

The arrow going from the circulatory system back to the respiratory system shows .

~potters6/te801/biology/biounits/respiration.htm

The basic repeating unit of nucleic acids are known as nucleotides. a nucleotide consists of three distinct chemical groups.

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.