You are presented with the question "What can have a long term effect on crops and weather conditions around the world?" and the following answer choices: 
- electromagnetic energy
 - A farmer irrigating his crops
 - deforestation
 - Nitrogen in the soil
 - Temperature
 - Use of fossil fuels
 - Burning fuel and air
 - A windy day

Now knowing that gases released during the use of fossil fuels causes global warming and global warming has great effect on crops and weather conditions around the world, choose the best answer.


 

      Use of fossil fuels   