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.
The heart, blood vessels, and blood are the parts that make up the circulatory system, which is defined as a closed system of blood vessels for the transport of gasses and nutrients. The circulatory system can be thought of as two circuits in one.