If frogs, toads and salamanders have a relatively complex circulatory system with a three-chambered heart, then what sort of circulatory system do frogs, toads, and salamanders share?

Answer choices:
- live birth
 - It helps them survive
 - matter vibrating
 - two-chambered heart
 - Veins and arteries.
 - biological diversity
 - three-chambered heart
 - four-chambered heart

 

       three-chambered heart   