You are presented with the question "Scrubbers can be used for what?" and the following answer choices: 
- Animal survival
 - storing water
 - hydrate their cells
 - water conservation
 - reducing acid rain
 - Relieve pain
 - root growth
 - protect them

Now knowing that the emission of sulfur dioxide causes acid rain and scrubbers significantly reduce emissions of sulfur dioxide, choose the best answer.


 

     reducing acid rain    