Fact 1: Absorbing energy causes objects to heat.

Fact 2: Crystal Balls Crystal balls have special uses as ritual objects.

Given the two facts above, answer the question "What causes crystal balls to heat?" with the following options: 
- Evaporation
 - increased mass
 - reflecting light
 - heating liquids
 - releasing energy
 - absorbing energy
 - decreased temperature
 - direct energy


 

      absorbing energy   