Fact 1: Energy enters ecosystems in the form of sunlight or chemical compounds.

Fact 2: If there is sun, there is sunlight, there is day.

Given the two facts above, answer the question "The sun contributes what to ecosystems?" with the following options: 
- sun spot
 - energy
 - darkness
 - seeds
 - positive
 - photons
 - Nutrients
 - Energy.


 

  energy       