Fact 1: Poison causes harm to living things.

Fact 2: Carbon monoxide and cyanide are poisons.

Given the two facts above, answer the question "what causes harm to living things?" with the following options: 
- toxins
 - vitamins
 - bacteria
 - cyanide
 - leeches
 - h2o
 - oxygen
 - Pesticides


 

    cyanide     