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

Fact 2: Mollusks have a simple heart, which pumps the blood throughout the body.

Given the two facts above, answer the question "what kind of heart do mollusks have?" with the following options: 
- organ
 - epidermal
 - fossils
 - ligt
 - three
 - warmth
 - warm
 - simple


 

        simple 