Question

Define open and closed circulatory systems.

Answer 1

A system required to transport oxygen and nutrients throughout the body.
The circulatory system is made up of blood vessels that carry blood away from and towards the heart.

Complete answer:
There are two types of circulatory system:
Open circulatory system – The blood flows freely through cavities and is not confined to blood vessels. It is mainly found in vertebrates.
Closed circulatory system – Where blood leaves the heart and travels through the blood vessels. It is present in vertebrates and echinoderms.
The circulatory system consists of three independent systems that work together: the heart, lungs, and arteries, veins, coronary, and portal vessels.

Difference between the open and closed circulatory system

Open Closed System	Closed Circulatory System
In an open circulatory system, the hemolymph directly bathes the organs and tissues.	In the closed circulatory system, it circulates within closed vessels.
In an open circulatory system, gases are not transported.	In a closed circulatory system, gases are transported.
In an open circulatory system blood flow is slow.	In a closed circulatory system blood flow is slow.
The open circulatory system is present in mollusks and arthropods.	The closed circulatory system is present in annelids and vertebrates.

Note: In an open circulatory system, the fluid flowing in the system is called hemolymph. In a closed circulatory system fluid flowing in the system is called blood. The pioneer of gas transportation is the respiratory system.