You are presented with the question "Birch trees are wood that are used to produce what?" and the following answer choices: 
- sweets
 - ice
 - water
 - energy
 - heat
 - food
 - sugar
 - paper

Now knowing that burning wood is used to produce heat and birch trees are deciduous and the wood burns hot and fast, as if soaked with oil or kerosene, choose the best answer.


 

     heat    