Fact 1: Alight bulb requires electrical energy to produce light.

Fact 2: Another use for electric heat is in regular light bulbs .

Given the two facts above, answer the question "what is used in light bulbs?" with the following options: 
- Decibels
 - batteries
 - energy
 - cellulose
 - Oak
 - magnetism
 - sunlight
 - water


 

   energy      