Which all phylum has open circulatory systems

Dear Student

Ans. Open circulatory system is seen in phylum Arthropoda and Mollusca.

The difference between Open and Closed circulatory system is given below:
 

Open Circulatory System	Closed Circulatory System
The blood is pumped by the heart into the body cavity or the haemocoel.	The blood is circulated through series of  blood vessels
Organs located in the haemocoel are bathed by blood.	Each organ has blood vessel which carry blood to it.
Blood flows slowly because there is no blood pressure after the blood leaves the blood vessels.	Blood flows at a high speed because there is high blood pressure after the blood leaves the heart
It is found in arthropods and molluscs.	It is found in Annelids and chordates.

 
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