Fact 1: Lung cancer is most often caused by exposure to tobacco smoke.

Fact 2: Lung cancer is the deadliest of all cancers.

Given the two facts above, answer the question "What is very deadly?" with the following options: 
- sticks
 - truth
 - insults
 - Pesticides
 - chlorofluorocarbons
 - Tobacco smoke
 - Electrical energy
 - forest is destroyed


 

      Tobacco smoke   