Which type of circulatory system do molluscs have? How can it be compared to the respiratory system of annelids?
Molluscs, with the exception of cephalopods, have an open circulatory system, i.e., the blood circulates within vessels, from the heart, but it also fills open lacunas or cavities. In annelids the circulatory system is closed, i.e., the blood circulates only inside blood vessels.
