Fact 1: Chordates have a complete digestive system and a closed circulatory system.

Fact 2: Chordates Chordates Chordates include fish, amphibians, reptiles, birds, and mammals.

Given the two facts above, answer the question "What kind of circulatory system do fish have?" with the following options: 
- open
 - solid
 - closed
 - three
 - stagnant
 - kinetic
 - complex
 - gills


 

   closed      