You are presented with the question "What does treating water remove before drinking it?" and the following answer choices: 
- direct damage to the lungs
 - h2o
 - an area swollen with pus
 - chlorine, pesticides, heavy metals
 - molecules
 - vapor
 - Mutagenic chemicals
 - nonliving organic matter

Now knowing that treating water is used to remove harmful substances before drinking and ordinary tap water can be full of harmful substances like chlorine, pesticides and heavy metals, choose the best answer.


 

    chlorine, pesticides, heavy metals     