You are presented with the question "How do aquatic animals get oxygen?" and the following answer choices: 
- photosynthesis
 - gills
 - rivers
 - blood
 - solutes
 - lungs
 - streams
 - carbon transfer

Now knowing that gills are used for breathing water by aquatic animals and animals breathe in oxygen and breathe out carbon dioxide, choose the best answer.


 

  gills       