Q. Which one of the following has an open circulatory system?

 3305  184 AIPMTAIPMT 2006Body Fluids and Circulation Report Error

Solution:

Periplaneta has open circulatory system i.e. the blood does not flow in blood vessels but flows in a haemocoel (body cavity). The circulatory systems of all vertebrates, as well as of annelids (for example, earthworms) and cephalopods (squid and octopus) are closed, in which the blood never leaves the system of blood vessels consisting of arteries, capillaries and veins.