You are presented with the question "What can be used to identify a liquid's boiling point?" and the following answer choices: 
- Acids
 - warmth
 - sodium
 - Urea
 - sugar
 - SO2
 - fire
 - energy

Now knowing that heating a liquid can be used to identify that liquid 's boiling point and fire has intense heat, choose the best answer.


 

       fire  