Fact 1: Absorbing sunlight causes objects to heat.

Fact 2: Collector panels absorb sunlight to heat air.

Given the two facts above, answer the question "what do collector panels use to heat objects?" with the following options: 
- Solar energy
 - Energy.
 - mechanical
 - energy
 - electricity
 - water
 - ice
 - sunlight


 

        sunlight 