Crate a diagram or cartoon to illustrate the experimental design described in this article. Your illustration can be fairly general but should show how the scientist did the overall experiment. (From biointeractive. org)

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.