Fact 1: If a tree falls then sunlight becomes available to the surrounding plants.

Fact 2: Plants use sunlight for photosynthesis.

Given the two facts above, answer the question "What can make photosynthesis more accessible to surrounding plants?" with the following options: 
- Energy.
 - a giant earthquake
 - circulatory systems
 - organic molecules
 - a tree falling
 - a huge fire
 - a great flood
 - Solar energy


 

     a tree falling    