Because its blood moves through vessels, or tubes in the body. In the head of the worm two large vessels meet and form five pairs of hearts which pumps blood through the vessels.
closed
closed circulatory system
open!
Earthworms have a closed circulatory system. Blood is pumped throughout its body by ringed blood vessels. An open circulatory system is not contained in vessels. In a closed circulatory system oxygen is carried in blood! hope this helps=)
The light bulb is a closed system: no mass transfer.
Closed System
an open circulatory system
closed.
Closed System
closed system
closed system
Amphibians have closed circulatory system Closed