You are presented with the question "What does not release particles?" and the following answer choices: 
- riding a bike
 - driving a car
 - influenza
 - monotremes
 - creating smog
 - burning coal
 - It remains dormant
 - peachleaf willow

Now knowing that riding a bike does not cause pollution and pollutants can be released either as gases or as particles, choose the best answer.


 

 riding a bike        