Fact 1: Gills are used for breathing water by aquatic animals.

Fact 2: All aquatic animals require dissolved oxygen to breathe.

Given the two facts above, answer the question "What do aquatic animals need to survive?" with the following options: 
- Water
 - gills
 - food
 - air
 - fishing
 - desert
 - history
 - warmth


 

  gills       