Fact 1: Mollusks have a circulatory system with one or two hearts that pump blood.

Fact 2: Clams are mollusks that live in the sea or in freshwater.

Given the two facts above, answer the question "what have a circulatory system with one or two hearts that pump blood" with the following options: 
- a fish
 - aorta
 - bacteria
 - animals
 - clams
 - plants
 - sharks
 - Birds


 

     clams    