What are the advantages of the closed circulatory system over the open circulatory system?
The closed circulatory system is more efficient. As blood circulates only inside blood vessels it can do it with more pressure reaching farther distances among the organs where hematosis occurs and the peripheral tissues. In addition the circulatory speed also heightens making possible more oxygen supply to great consuming tissues, as the muscle tissues that then can perform faster movements. Animals with an open circulatory system (with the exception of insects that do gas exchange independently from the circulation) are generally slower and have a low metabolic rate.