Why blood flow in a leg vein is slow when there is lack of movement?

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.

Prompt: write about whether or not you plan to register to vote when you are 18 and what political party preference (if any) you will disclose. explain the reasons for your decisions.