Fact 1: The color of leaves on deciduous trees usually changes in the autumn season.

Fact 2: Deciduous trees are Oak, Elm, Ash, Maple, and Birch.

Given the two facts above, answer the question "What usually changes in the autumn season?" with the following options: 
- Something that can be auburn
 - looseness of dirt or compost
 - the looseness of soil
 - the color of leaves on oaks
 - a hemisphere is tilted away from the sun
 - Warm air moving into cold air
 - the male sex cells of plants
 - The bending of a ray of light


 

    the color of leaves on oaks     