Fact 1: The Earth revolving around the Sun causes the seasons to change on its axis.

Fact 2: Gold, scarlet, and auburn leaves make a mosaic of rich colors heralding seasonal change.

Given the two facts above, answer the question "What factor is instrumental behind the change of leaf colors during the year?" with the following options: 
- organisms and their habitat
 - global warming
 - Earth orbiting the Sun
 - Solar energy
 - scattered light
 - Greenhouse gases
 - Varying light output from sun
 - Moon orbiting the Earth


 

   Earth orbiting the Sun      