Fact 1: The Earth being tilted on its rotating axis causes seasons.

Fact 2: Summer is a bold season.

Given the two facts above, answer the question "What does the Earth being tilted on its rotating axis cause?" with the following options: 
- wind
 - the galaxy
 - summer
 - spring
 - rainfall
 - heat
 - the moon
 - the solar system


 

   summer      