You are presented with the question "What causes yearly temperature variations?" and the following answer choices: 
- earth's rotation
 - scattered light
 - earth's bend on rotating axis
 - exposure to cold
 - depress neuronal excitability
 - earth's tilt on rotating axis
 - wind and erosion
 - earth's tilt on rotating half

Now knowing that the Earth being tilted on its rotating axis causes seasons and latitude and season cause temperature variations, choose the best answer.


 

      earth's tilt on rotating axis   