You are presented with the question "What causes clear weather?" and the following answer choices: 
- our nearest star
 - electromagnetic energy
 - looseness of dirt or compost
 - Animal survival
 - The area was once underwater
 - evaporation
 - barometric pressure
 - windpower operated machines

Now knowing that high pressure systems cause clear weather and high barometric pressure indicates clear weather, choose the best answer.


 

       barometric pressure  