You are presented with the question "When fish convert oxygen in water to oxygen in blood this is called?" and the following answer choices: 
- evaporation
 - barrel-shaped
 - motility
 - Heart rate
 - squeeze
 - breathing
 - hormones
 - survival

Now knowing that breathing is when a gill converts from oxygen in water into oxygen in blood and all fish have gills , choose the best answer.


 

      breathing   