You are presented with the question "what have a circulatory system?" and the following answer choices: 
- protist
 - fur seals
 - veins
 - mammals
 - animals
 - bacteria
 - mussels
 - sharks

Now knowing that mollusks have a circulatory system with one or two hearts that pump blood and mussels are bivalve mollusks, choose the best answer.


 

       mussels  