Located in plant cells are large irregular shaped green structures called chloroplasts. They are green because they contain a green pigment called chlorophyll.
An open circulatory system is a type of circulatory system in which nutrients and waste are moved through the body with the assistance of a fluid which flows freely through the body cavity, rather than being contained in veins.
It is also a closed system in the sense that blood does not enter or leave the system during its journey from the heart to the body and back again. In such a system, a continuous flow of the same liquid can be pumped through the loop again and again. The circulatory system is comprised of five main parts: The Heart.