You are presented with the question "What causes days to change?" and the following answer choices: 
- Space travel
 - recovery time from fatigue
 - Earth orbiting the Sun
 - sunlight
 - earthquakes
 - Solar energy
 - prolonged thirst
 - global warming

Now knowing that earth orbiting the Sun causes seasons to change and days and hours change seasonally, choose the best answer.


 

   Earth orbiting the Sun      